Icd manual

TRAINING WORK BOOK
ON
International Classification of Diseases
-The 10th revision (ICD 10)
IInnffoorrmmaattiioonn aanndd SSttaattiissttiiccss DDeeppaarrttmmeenntt
National Information Center-Ministry Of Health

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ICD-10 Work book- IInnffoorrmmaattiioonn aanndd SSttaattiissttiiccss DDeeppaarrttmmeenntt
CONTENTS
SSuubbjjeecctt PPaaggee NNoo..
1. Introduction To ICD-10 Structure and Principles of Classification………………….…….6
What is clinical coding?
What is a statistical classification?
Why use a classification?
History of the International Classification of Diseases
Overview of the ICD-10 classification
Volumes of the ICD-10
Chapters of the ICD-10
Structure of the ICD-10 code
2. Volume 1 - Tabular List ………………………………………………………….………….11
Important points regarding the Tabular List
Chapters using more than one letter:
Blocks
Three character categories or rubrics
Four character categories or rubrics
Conventions
Inclusion Terms
Exclusion Terms
Glossary descriptions
Dagger and Asterisk convention
Parentheses ( )
Square brackets [ ]
Co1lon :
Brace }
Not Otherwise Specified (NOS)
N1ot elsewhere classified (NEC)
"A1nd" in code titles
Point dash
3. Volume 3 - Alphabetic Index………………………………………………………………….17
Important points regarding the Alphabetic Index
Structure of Index entries
Conventions
Parentheses ( )
Not Elsewhere Classified (NEC)
Cross-references
4. Overview of Morbidity Coding ……………………………………………………..……….22
Sources of morbidity data
Uses of morbidity data
Central concepts for morbidity coding
Why single-condition coding?
Rules for reselection of main condition

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Guidelines for coding of the main condition and other
Optional additional codes
5. Overview of Mortality Coding ………………………………………………………………28
Important points for mortality coding chapter
International Form of Medical Certificate of
Concept of underlying cause of death:
Selecting the underlying cause of death
General Principle:
Rule 1
Rule 2
Rule 3
Rules for modification:
Rule A. Senility and other ill-defined conditions
Rule B. Trivial conditions
Rule C. Linkage
Rule D. Specificity
Rule E. Early and late stages of disease
Rule F. Sequelae
Assumption of intervening cause
Highly improbable
Duration
Nature of injury
Malignancy
6. Chapter- specific notes ……………………………………………….………………………37

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Introduction to ICD-10 Structure
and
Principles of Classification

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Introduction to ICD-10 Structure and Principles of Classification
What Is Clinical Coding?
Clinical coding is the translation of diagnoses of diseases, health related problems and procedural concepts
from text to alphabetic/numeric codes for easy storage, retrieval and analysis.
What is a statistical classification of diseases?
A classification of diseases is a system of categories or groupings to which diseases, injuries, conditions and
procedures are assigned according to established criteria. It is the element of grouping similar terms, which
distinguishes a statistical classification from a nomenclature. A nomenclature requires a separate name or title
for each disease or procedure concept.
ICD-10 is a statistical classification, which means that it contains a limited number of mutually exclusive
code categories, which describe all disease concepts. The classification is hierarchical in structure with
subdivisions to identify broad groups and specific entities. The classification includes specific rules to guide
its use.
Why use a classification?
 To allow easy storage, retrieval and analysis of data.
 To allow systematic recording, analysis, interpretation and comparisons of mortality and morbidity
data between hospitals, provinces or countries.
 To allow comparisons in the same location across different time periods.
Historyof the International ClassificationofDiseases
The theory of disease classification began in the 17th Century when John Graunt recognized the need to
organize mortality data into some logical form and therefore developed the first statistical study of disease,
called the London Bills of Mortality. In this work, Graunt classified the deaths of all children who were born
alive but who died before they reached the age of six. Death were classified as due to thrush, convulsions,
rickets, teeth and worms, chrysomes, livergrown, smallpox, swine pox, measles and worms without
convulsions. It was hoped that clues regarding the nature and etiology of these diseases would be brought to
light and that this understanding would ultimately lead to better treatments.
During the 18th Century, Sauvages first attempted to systematically classify all diseases in a work called
"Nosologia Methodica".
William Farr, the first medical statistician, who worked in the newly formed General Register Office of
England and Wales in the mid-1800s, further developed the work of both of these men. Farr's work formed
the basis of a recommendation to create the International List of Causes of Death, which was presented to
the first International Statistical Congress, held in Brussels in 1853. Although modified in 1874, 1880 and
1886 to suit the needs of the time, Farr's classification did not receive universal acceptance, despite his best
efforts to promote it.
The general arrangement of the classification which included the principle of classifying diseases according to
body site - became the basis for work carried out by Dr Jacques Bertillon from Paris. Bertillon developed a
classification that distinguished between diseases that affected the body as a whole (systemic diseases) and
those that were localised to a particular body site. The Bertillon Classification of Causes of Death received
general approval and was adopted for use by several countries. When the American Public Health Association
recommended its use for Canada, Mexico and the USA, it also developed plans for the updating of the
classification every ten years. At this time, in the very early 1900s, there were only 179 groups of causes of

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death! In 1920, the Health Organization of the League of Nations, which had taken an active role in the
collection and classification of death statistics, determined that it would take over the management of the
Causes of Death classification. When revising the classification for the fourth and fifth times, in 1929 and
1938, this organization included classifications for non-fatal conditions for the first time.
In 1946, the Interim Commission of the World Health Organization was charged with the responsibility for
the continued revision of the classification. The sixth revision conference marked a milestone in the collection
of health and vital statistics. A new publication entitled "International Classification of Diseases, Injuries and
Causes of Death" was issued in 1948, based on the previous work but including recommendations for the
collection of morbidity data, as well as mortality statistics. This classification underwent minor amendment in
1955 and 1965 but mainly to correct errors of fact and inconsistencies. The 1965 revision included, for the
first time, two volumes - a tabular list and an alphabetical index.
In 1975, the 46 member states of the WHO convened in Geneva to begin development of the ninth revision of
the ICD, as it came to be known. In addition to the member states, a number of medical specialty groups sent
representatives, due to the now almost universal interest in using the classification for medical record coding
and indexing, monitoring and evaluation of health services and epidemiological research. The next year, the
World Health Assembly agreed to the revision of the classification and to the development, on a trial basis, of
a procedure classification as an accompaniment to the disease classification. Thus the ICD-9 and ICPM
(International Classification of Procedures in Medicine) were introduced.
Work on the tenth revision of the International Classification of Diseases began in September 1983 when a
preparatory meeting on ICD-10 was convened by the World Health Organization in Geneva. This was
followed by several meetings of an expert committee in 1984 and 1987 to make decisions on the direction the
work should take and the form of the final proposal. In addition to the technical contribution provided by the
expert committees, a large number of comments and suggestions were received from WHO member states
and regional offices as a result of the worldwide circulation of the draft proposals for revision and review.
It became clear that many users wished the ICD to encompass types of data other than simply diagnostic
information. Even if it was restructured, the ICD could not cope with the extremes of the requirements. The
concept was therefore developed of a "family" of classifications, with the main ICD as the core, covering the
traditional mortality and morbidity statistics, while the needs for more detailed or different classifications
would be dealt with by other members of the family such as the International Classification of Functioning
(ICF) and the Diagnostic and Statistical Manual of Mental Disorders (DSM).
Several alternative models for the restructure of the main ICD were investigated, and the final decision was to
use an alphanumeric system, which would give a better balance to the chapters and allow sufficient space for
future additions and changes without disrupting the codes.
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ICD-10 is part of the ICD family of classification systems, which also includes:
 International Classification of Functioning, Disability and Health (ICF)
 International Classification of Diseases for Oncology (ICD-O)
 Application of the International Classification of Diseases to Dentistry and Stomatology (ICD-DA)

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 Application of the International Classification of Diseases to Rheumatology and Orthopaedics (ICD-
R&O), including the International Classification of Musculoskeletal Disorders (ICMSD).
Overview of the ICD-10 classification
ICD-10 is a variable-axis classification - meaning the epidemiological data and statistical data coded to it may
be grouped as follows:
•epidemic diseases
•constitutional or general diseases
•local diseases arranged by site
•developmental diseases
•injuries
There are three (3) main elements to the structure of the ICD-10. They are:
1.there are 3 volumes
2.there are 21 chapters
3.the structure of the code is alphanumeric.
Volumes of the ICD-10
Volume 1 is the TTaabbuullaarr lliisstt, which is an alphanumeric listing of diseases and disease groups,
along with inclusion and exclusion notes, some coding rules, special tabulation lists for
mortality and morbidity, definitions and regulation.
Volume 2 is IInnssttrruuccttiioonn MMaannuuaall. It provides :
•an introduction to, and instructions on how to use volumes 1 and 3
•guidelines for certification and rules for mortality coding
•guidelines for recording and coding for morbidity coding
•Statistical presentation
Volume 3 is the comprehensive AAllpphhaabbeettiiccaall iinnddeexx of the diseases and conditions found in
the Tabular list.
Chapters of the ICD-10
The ICD-10 contains 21 chapters, each of which is identified by a Roman Numeral i.e. I, II,
III, IV, V etc. When referring to a chapter, you should call it by its chapter number and not by
the letters of the codes associated with it. i.e. refer to Diseases of the Digestive System as
Chapter XI and not as the K chapter. This is because some chapters contain more than one
letter and some letters are used in more than one chapter
Structure of the ICD-10 code
The first character of the code is an alpha character, followed by two, three or four numeric characters.

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The structure of the three-character category is:
Most three-character categories are further subdivided into sub-categories to enable coding of a disease or
condition more specifically.
NOTE: In some countriesand data collection systems, the decimal point may not be used,but for the purposes of this
course the decimal point should be included in all exercises.

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Volume 1 Tabular List

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Volume 1 - Tabular List
Important points regarding the Tabular List
•Most chapters are associated with particular body systems, special diseases or external factors. There is,
however, one exception which is Chapter XVIII “Symptoms, signs and abnormal clinical and laboratory
findings, not elsewhere classified”.
•The number of categories assigned to a chapter is influenced by the number of diseases and conditions that
fall within the scope of the chapter.
•Fourteen of the chapters have a single letter assigned to them and use most of the 100 categories available.
For example, Chapter XI contains codes ranging from K00 to K93. The codes K94 to K99 have not been
used at this stage and have been left vacant for future additions to the classification.
•Three chapters have a smaller range of categories assigned to them and share letters.
•Four chapters use more than one letter in defining categories. e.g. Chapter II contains codes beginning with C
and D.
Chapters using more than one letter:
Chapter I Certain infectious and parasitic diseases A,B
Chapter II Neoplasms C,D
Chapter XIX Injury, poisoning and certain other
consequences of external causes S,T
Chapter XX External causes of morbidity and mortality V,W,X,Y
Chapters using same letter
Chapters II & III – ‘D’ ; Chapters VII & VIII – ‘H’
Look at titles of the chapters of the ICD-10. The chapter titles indicate that the conditions included are wide
ranging, therefore a large number of codes are required to cover all the conditions. Using an alpha character at
the beginning of the code has allowed for 2,600 available 3-character codes. This in turn allows for a large
number of 4 character subcategories. Each 3-character code can have up to 10 subcategories.
Blocks
Each chapter has been divided into blocks of related conditions. The blocks are then divided into three, four
and five digit categories.
Three character categories or rubrics
Some blocks have three character categories for single conditions. Other blocks contain groups of diseases.
Four character categories or rubrics
These are not mandatory for reporting at international level but the use of fourth characters adds detail and
specificity to the coded data. The use of fourth characters allows up to ten subcategories.

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The fourth character ‘8 is generally used for “other” conditions belonging to the three character category, and
‘9 conveys similar meaning as the three character category title, without adding any additional information.
Conventions
The ICD-10 Tabular List (Volume I) makes use of certain abbreviations, punctuations, symbols and
instructional terms which must be clearly understood. These are referred to as the coding conventions.
Inclusion Terms
Within the three and four character rubrics there are usually listed a number of other diagnostic terms in
addition to the code title. These are known as "inclusion terms" and are given as examples of diagnostic
statements to be classified to that rubric. They may refer to different conditions or be synonyms. They are not
a sub-classification of the rubric. They are to be used as a guide to the content of the rubric, keeping in mind
that the list is not exhaustive.
e.g. G91 Hydrocephalus includes acquired hydrocephalus
Exclusion Terms
Certain rubrics contain lists of conditions preceded by the word "Excludes". These terms are to be coded
elsewhere, not within this category as the code may suggest. The correct code that should be assigned is in
parentheses following the term.
e.g. Q74 Other congenital malformations of limb(s) excludes polydactyly (Q69.-), reduction defect of
limb (Q71-Q73), syndactyly (Q70.-)
Glossary descriptions
Chapter V Mental and Behavioral Disorders, uses glossary descriptions to indicate the content of rubrics.
This device is used because the terminology of mental disorders varies greatly, particularly between different
countries and the same name may be used to describe quite different conditions. The glossary is not intended
for use by coding staff to make a diagnosis but is intended as a guide for clinicians to indicate the content of
the rubric.
Dagger and Asterisk convention
The dual coding system of creating combinations of codes through attachment of daggers (†) and asterisks (*)
has been used in ICD-10, thus allowing the description of a condition in terms of its underlying cause or
aetiology (†) and current manifestation (*). This enables a better description of the medical care provided and
resources used in its treatment to be given.
Using this convention, two codes are assigned for diagnostic statements that contain information about both
an underlying generalized disease and a manifestation in a particular organ or site, which is a clinical problem
in its own right.
The primary code is for the underlying disease and is marked with a dagger (†). An optional code for the
manifestation is marked with an asterisk (*). It is a basic principle of the ICD that the dagger code is the
primary code and must always be used for single condition coding. An asterisk code should never be used
alone. When coding underlying cause of death for mortality purposes, the dagger code should be used, never
an asterisk code.

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Dagger and asterisk codes convey different meanings in combinations depending upon the
circumstances of placing the signs.
‘+’ with * mark in heading denotes same code used for the conditions listed below it.
e.g. A 170 + Tuberclulosis memingeo (areoral) (spinal)
tuberenlons up to memingitis
+ without * in the heading but mentioned in codes in parespests below it denotes that different codes
are available for the conditions following the dianosis in the heading
e.g A 18.1 +Tuberonlosis of genitourinary system
Tuberculosis of:
Bladder (N 33.0*)
Cervix (or 74.0*)
None of the symbols ‘+’ & * present in title/heading indicates that there are individual terms with
alternative codes.
e.g. A 54.8 other gonococcnl infections
Gonococcal:
Peritonitis + (K 67.1*)
Pneumonia + (J17.0*)
Septicasmia
There are 83 asterisk categories in ICD-10 (listed at the start of relevant chapters) which may be used in
conjunction with a dagger code, but must not be used alone. Asterisk categories are listed at the beginning of
each chapter, block and rubric where appropriate.
Parentheses ( )
Parentheses are used in four ways in Volume 1:
1. To enclose supplementary words, which may follow a diagnostic term without affecting the code
number to which the words outside the parentheses would be assigned.
e.g. G11.1 Early-onset cerebellar ataxia Friedrich’s ataxia (autosomal recessive)
2. To enclose the code to which an exclusion term refers.
e.g. B25 Cytomegaloviral disease excludes congenital cytomegalovirus infection (P35.1)
3. To enclose the three-character codes of categories in a particular block.
e.g. Diseases of peritoneum (K65-K67)
4. To enclose the dagger code in an asterisk category or the asterisk code in a dagger term.
e.g. K77.0* Liver disorders in infectious and parasitic diseases classified elsewhere
Hepatitis
- cytomegaloviral (B25.1†)
Square brackets [ ]:
Square brackets are used:

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1- For enclosing synonyms, alternative words or explanatory phrases.
e.g. A84.0 Far Eastern tick-borne encephalitis [Russian spring-summer encephalitis]
2. For referring to notes.
e.g. C21.8 Overlapping lesion of rectum, anus and anal canal [see note 5 on page 182]
3. For referring to a previously stated set of fourth character subdivisions common to a number of
categories. e.g. F10.-Mental and behavioural disorders due to use of alcohol [see pages 321-323 for
subdivisions]
Colon :
The colon [:] is used in listings of inclusion and exclusion terms when the words that precede it are not
complete terms for assignment of the diagnosis to that rubric. In other words, the words require one or more
of the modifying or qualifying words indented under the lead term before the diagnosis can be assigned to the
rubric.
e.g. G71.0 Muscular dystrophy: autosomal recessive
benign
distal
…
Brace }
A brace is used in listings of inclusion and exclusion terms to indicate that neither the words that precede it
nor the words after it are complete terms. In other words, one or more of the terms that follow the brace
should be part of the diagnosis, to qualify any of the terms before the brace.
e.g. E10.1 Insulin dependent diabetes mellitus with ketoacidosis
See the brace under the entry for the relevant fourth character
1. With ketoacidosis
Diabetic:
Acidosis } without mention of coma
Ketoacidosis }
Not Otherwise Specified (NOS)
NOS is an abbreviation for 'not otherwise specified', implying 'unspecified' or 'unqualified'.
Coders should be careful not to code a term as unqualified unless it is quite clear that no other information is
available that would permit a more specific code assignment from elsewhere in the classification.
e.g. K14.9 Disease of tongue, unspecified
Glossopathy NOS
Not elsewhere classified (NEC)
NEC stands for not elsewhere classified. When used in a three-character category title, NEC serves as a
warning that certain specified types of the listed conditions may appear in other parts of the classification.
e.g. K73 Chronic hepatitis, not elsewhere classified

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"And" in code titles
In Volume 1 of ICD-10, "and" stands for "and/or".
e.g. S49.9 Unspecified injury of shoulder and upper arm means Unspecified injury of shoulder or
unspecified injury of upper arm or unspecified injury of shoulder and upper arm.
Point dash .-
When used as a replacement for the fourth character of a subcategory, a point dash [.-] indicates to the coder
that a fourth character exists and should be sought in the appropriate category in the Tabular list.
e.g. D59.1 Other autoimmune haemolytic anaemias
Excludes haemolytic disease of fetus and newborn (P55.-)

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Volume 3 Alphabetical Index

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Volume 3 - Alphabetic Index
Important points regarding the Alphabetic Index
•Volume 3 is an alphabetic index to the Tabular Listing of Volume 1. As such, it contains far more diagnostic
terms than the tabular list, reflecting the many and varied ways that doctors and other clinical staff describe
diseases.
•Volume 3 consists of:
•An Introduction, explaining the purpose of the index, its general arrangement and conventions used in
the index
•Section I which is an alphabetic listing of terms relating to diseases, nature of injury, reasons for
contact with health services and factors influencing a person’s health
•Section II which is an alphabetic listing of external causes of injury, morbidity and mortality
•Section III, which is an alphabetically arranged table of drugs and chemicals.
Structure of Index entries
Index entries contain:
• Lead terms (usually nouns, sometimes adjectives e.g. carious, tuberculous etc) to the far left of each
column, in bold. They refer mainly to the names of diseases or conditions.
• Modifiers at different levels of indentation to the right. They usually refer to varieties of sites or
circumstances that affect coding. Modifiers which do not affect code assignment appear in parentheses ( )
after the condition. All modifiers appear in alphabetical order except “with” which always appears first.
e.g. to code a bilateral inguinal hernia with gangrene and obstruction, firstly identify the lead term
(hernia), then follow the series of indentations in the Index until all of the diagnosis description has
been covered.
Hernia
- inguinal
-- bilateral
--- with
---- gangrene (and obstruction) K40.1
Note that there are often many entries at each level of indentation and it is necessary to be careful in
following the trail of relevant entries for your diagnosis under each lead term.
• Code numbers follow the terms in the index and may appear as a 3-character category or be subdivided
with either the appropriate 4th digit or a dash (.-). Where the dual system of coding († and *) applies, both
codes are given in the index. The dagger is always mentioned first, followed by the asterisk code.
•If you cannot identify the lead term in the Index, there are a number of standard ways that codes can be
found. Try using one of the following ‘generic’ lead terms:

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disease
complication
syndrome
pregnancy
labour
delivery
puerperal
maternal condition affecting fetus or newborn
injury
sequelae
suicide
assault
legal intervention
war operations
counselling
observation
examination
history
problem
screening
status
vaccination
NOTE: American spelling is used throughout Volume 3, with cross-references wherever diphthongs
appear at the beginning of a term
eg. Oesophag(o) ... -see Esophag(o) ...
However, in Volume 1 so-called English spelling is used. For example: look up Haemochromatosis
with refractory anaemia
Conventions
Parentheses ( )
Parentheses are used in the same way as in Volume 1, to enclose non-essential modifiers which do not affect
code assignment. e.g. Deafness (acquired)(complete)(hereditary)(partial) H91.9
Not Elsewhere Classified (NEC)
"Not elsewhere classified" indicates that specified variants or types of the disease are classified elsewhere, and
that where appropriate, a more precise term should be looked for in the Index. If the specific diagnostic term
cannot be found in the Index, then the NEC code can be used indicating that the condition does not have a
unique code elsewhere in the classification.
e.g. Mastoiditis (coalescent)(haemorrhagic)(suppurative) H70.9
- acute, subacute H70.0
- chronic (necrotic)(recurrent) H70.1
- specified NEC H70.8

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Cross-references
Cross references are used to avoid unnecessary duplication of terms in the Index.
"See" requires the coder to refer to the other term. This is a mandatory instruction.
e.g. Ingestion
- chemical -see Table of Drugs and Chemicals
"See also" directs the coder to refer elsewhere in the Index if the statement being coded contains other
information that is not found indented under the term to which "see also" is attached. This helps the coders to
find the most specific code possible for the diagnosis being coded.
e.g. Injury (see also specified injury type)
It is imperative that Volumes 1 and 3 be used together in locating codes to accurately describe each clinical
case - coders should not fall into the trap of coding straight from the Alphabetical Index or browsing
around the Tabular List looking for a code that seems to fit the case being coded.

1199
Basic Coding Guidelines
Basic Coding Guidelines
When coding you must use the Alphabetical Index as well as the Tabular List. These guidelines should be
followed when coding using ICD-10.
1. Identify the type of statement to be coded and refer to the appropriate section of the Alphabetical Index. (If
the Statement is a disease or injury or other condition classifiable to Chapters I-XIX or XXI, consult Section I
of the Index. If the statement is the external cause of an injury or other event classifiable to Chapter XX,
consult Section II.
2. Locate the lead term. For diseases and injuries this is usually a noun for the pathological condition.
However, some conditions expressed as adjectives or eponyms are included in the Index as lead terms.
3. Read and be guided by any note that appears under the lead term.
4. Read any terms enclosed in parentheses after the lead term, as well as any terms indented under the lead
term, until all the words in the diagnostic term have been accounted for.
5. Follow carefully any cross-references ("see" and "see also") found in the Index.
6. Refer to the Tabular List to verify the suitability of the code number selected.
7. Be guided by any inclusion or exclusion terms under the selected code or under the chapter, block or
category heading.
8. Assign the code.

2200
Overview of Morbidity Coding

2211
OOvveerrvviieeww ooff MMoorrbbiiddiittyy CCooddiinngg
This section covers the coding of diagnoses and other reasons for contact with health services.
Prior to 1948, the International Classification of Diseases was used only for mortality coding. With the 6th
revision of ICD in 1948 came the recognition of its potential for morbidity coding. The 6th revision then
became an expanded version that included codes for non-fatal conditions. This expansion has continued ever
since - there has been a steady increase in the number of categories for coding non-fatal conditions and other
health-related circumstances.
For the purposes of ICD, the term morbidity covers illness, injuries and reasons for contact with health
services including screening and preventive care. Coding usually relates to an episode of health care in a
health institution but may also apply to surveys or other diagnostic data.
Morbidity usually relates to a single episode of health care. An episode of health care may be defined as:
•A period of inpatient care;
or
•A contact (or series of contacts in a specific time period) with a health care practitioner in relation to the
same condition or its immediate consequences.
Sources of morbidity data
Sources of data for morbidity coding include:
•Hospital records
•School medical records
•Death certificates
•Armed services records
•Occupational medical records
•Health surveys
•Outpatient records (ambulatory care)
•Maternal and child health services records
•Disease surveillance records e.g. vaccine preventable diseases, HIV etc.
•Cancer and chronic disease registry records
•Other
Uses of morbidity data
Morbidity data may be used, among other things, to provide clues to causes of disease, and it may form the
basis on which decisions are made about previous measures or the allocation of resources or priorities for
disease prevention programs.
Central concepts for morbidity coding
• At the end of an episode of care, the clinician should record all conditions which affected the patient in
that period.
• Practice may vary from establishment to establishment or health authority to health authority - in some

2222
places, one diagnosis will be singled out for coding (single-condition coding) while in other places, all
diagnoses will be coded for each episode of care (multi-condition coding). Coders need to be aware of the
policy of their establishments in this regard.
Why single-condition coding?
Some establishments may implement this policy because of lack of resources (e.g. coding, administrative) or
because the resultant simpler data may be more appropriate for its needs. With single-condition coding, there
is the need to choose the main condition from the set of diagnoses so that it can then be coded.
TThhee mmaaiinn ccoonnddiittiioonn iiss ddeeffiinneedd aass tthhee ccoonnddiittiioonn,, ddiiaaggnnoosseedd aatt tthhee eenndd ooff tthhee eeppiissooddee ooff hheeaalltthh ccaarree,, pprriimmaarriillyy
rreessppoonnssiibbllee ffoorr tthhee ppaattiieenntt’’ss nneeeedd ffoorr ttrreeaattmmeenntt oorr iinnvveessttiiggaattiioonn.. IIff tthheerree iiss mmoorree tthhaann oonnee ssuucchh ccoonnddiittiioonn,, tthhee
oonnee hheelldd mmoosstt rreessppoonnssiibbllee ffoorr tthhee ggrreeaatteesstt uussee ooff rreessoouurrcceess sshhoouulldd bbee sseelleecctteedd.. IIff nnoo ddiiaaggnnoossiiss wwaass mmaaddee,, tthhee
mmaaiinn ssyymmppttoomm,, aabbnnoorrmmaall ffiinnddiinngg oorr pprroobblleemm sshhoouulldd bbee sseelleecctteedd aass tthhee mmaaiinn ccoonnddiittiioonn……BByy lliimmiittiinngg tthhee
aannaallyyssiiss ttoo aa ssiinnggllee ccoonnddiittiioonn ffoorr eeaacchh eeppiissooddee,, ssoommee aavvaaiillaabbllee iinnffoorrmmaattiioonn mmaayy bbee lloosstt..
IItt iiss tthheerreeffoorree rreeccoommmmeennddeedd,, wwhheerree pprraaccttiiccaabbllee,, ttoo ccaarrrryy oouutt mmuullttiippllee ccoonnddiittiioonn ccooddiinngg aanndd aannaallyyssiiss ttoo
ssuupppplleemmeenntt tthhee rroouuttiinnee ddaattaa..
Clinicians and coders will have no trouble in choosing a main condition if the patient is treated for only one
condition during an episode of care but many cases are not that simple.
What distinguishes the main condition (MC) from the rest of the recorded conditions?
••TThhee mmaaiinn ccoonnddiittiioonn iiss tthhee ddiiaaggnnoossiiss eessttaabblliisshheedd aatt tthhee eenndd ooff tthhee eeppiissooddee ooff hheeaalltthh ccaarree ttoo bbee tthhee
ccoonnddiittiioonn pprriimmaarriillyy rreessppoonnssiibbllee ffoorr tthhee ppaattiieenntt rreecceeiivviinngg ttrreeaattmmeenntt oorr bbeeiinngg iinnvveessttiiggaatteedd ii..ee.. tthhaatt
ccoonnddiittiioonn wwhhiicchh iiss ddeetteerrmmiinneedd aass bbeeiinngg mmaaiinnllyy rreessppoonnssiibbllee ffoorr tthhee eeppiissooddee ooff hheeaalltthh ccaarree..
What then are other conditions (OC) which might be coded?
•OOtthheerr ccoonnddiittiioonnss aarree ddeeffiinneedd aass tthhoossee tthhaatt ccooeexxiisstt oorr ddeevveelloopp dduurriinngg tthhee eeppiissooddee ooff hheeaalltthh ccaarree aanndd
aaffffeecctt tthhee mmaannaaggeemmeenntt ooff tthhee ppaattiieenntt..
Rules for reselection of main condition
In some instances, the Main Condition recorded by the clinician may not be consistent with the WHO
definition. Alternatively, no Main Condition may have been specified. WHO has developed a set of rules that
can be used to ensure that the Main Condition selected and coded reflects the condition mainly responsible for
the episode of care. Coders need to be familiar with these rules and be able to apply them.
MB1. Minor condition recorded as main condition, more significant condition recorded as other
condition.
•Where a minor or longstanding condition, or an incidental problem, is recorded as the main condition, and a
more significant condition, relevant to the treatment given and/or the specialty that cares for the patient, is
recorded as an other condition, reselect the latter as the main condition

2233
MB2. Several conditions recorded as main condition.
•If several conditions that cannot be coded together are recorded as the main condition, and other details on
the record point to one of them as the main condition for which the patient received care, select that condition.
Otherwise select the condition first mentioned.
MB3. Condition recorded as main condition is presenting symptom of diagnosed, treated condition
•If a symptom or sign (usually classifiable to Chapter XVIII), or a problem classifiable to Chapter XXI, is
recorded as the main condition and this is obviously the presenting sign, symptom or problem of a diagnosed
condition recorded elsewhere and care was given for the latter, reselect the diagnosed condition as the main
condition.

2244
MB4. Specificity
•Where the diagnosis recorded as the main condition describes a condition in general terms, and a term that
provides more precise information about the site or nature of the condition is recorded elsewhere, reselect the
latter as the main condition.
MB5. Alternative main diagnoses
•Where a symptom or sign is recorded as the main condition with an indication that it may be due to either
one condition or another, select the symptom as the main condition. Where two or more conditions are
recorded as diagnostic options for the main condition, select the first condition recorded.

2255
Guidelines for coding of the main condition and other conditions
 Selection of the main condition should be done by the clinician caring for the patient or may, if
necessary, be identified at the time of coding, by application of the rules for reselection.
 Once the main condition has been selected correctly, you may then code the case, following normal
procedures.
 The dagger and asterisk codes should be used together, wherever possible, because they describe
different aspects of the condition. The dagger code is the preferred main condition.
 Injuries may be classified by their nature (Chapter XIX) and by the external cause that led to the injury
(Chapter XX). Both codes should be used but the nature of the injury code is the preferred main
condition for morbidity coding.
 Where the patient is suffering an acute exacerbation of a chronic illness and there is no combination
category available, the acute aspect of the condition should be assigned as the preferred main
condition, with the chronic aspect as an optional additional code.
Postprocedural conditions and complications
The code range T80-T88 (Chapter XIX) is available to classify certain complications relating to surgical and
other procedures. Complications coded here generally affect the whole body. Other categories are also
provided near the end of most body system chapters for conditions which occur either as a consequence of
specific procedures and techniques or as a result of the absence of an organ or postprocedural conditions
which affect a specific body system.
Postprocedural conditions or complications are defined as:
conditions caused by acquired absence of an organ;
any conditions resulting from surgical procedures;
the after-effect of radiotherapy or similar treatment.
Some conditions are common post procedurally. They are coded in the normal way but an additional code
may be used to identify the relationship of the condition to a previous procedure.The additional code would be
assigned from Chapter XX, External causes of morbidity and mortality (Y83 and Y84).
When a postprocedural condition or complication is recorded as the main condition, it is essential that the
coder refers to modifiers in the Index to ensure arrival at the correct code.

2266
Overview of Mortality Coding

2277
Overview Of Mortality Coding
Important points for mortality coding:
•The International Classification of Diseases has its origins in the preparation of mortality statistics.
•Death certificates are the main source of mortality data. Information on death certificates may be provided by
either a health practitioner or in the case of accidents or violent deaths, a coroner. In some jurisdictions,
another official (who may not be medically trained) is responsible for the completion of the medical
certificate of cause of death.
•The person certifying the cause of death will enter the sequence of events leading to the death on the death
certificate in the international format specified by WHO.
International Form of Medical Certificate of Cause of Death

2288
Concept of underlying cause of death:
Many Death Certificates give only a single cause of death. These are relatively simple to deal with and all
you have to do is ccooddee tthhee ssiinnggllee ccaauussee. However, in many other cases, two or more morbid conditions
contribute to death. These must all be recorded on the certificate. In such cases it has been the practice in
vital statistics to select one of the causes of death for coding and reporting purposes. This single cause is
called the Underlying Cause of Death.
The concept of the underlying cause of death is central to mortality coding.
WHO has defined the underlying cause of death as:
 the disease or injury which initiated the train of morbid events leading directly to
death; or
 the circumstances of the accident or violence which produced the fatal injury.
Therefore, the underlying cause of death is the condition, event or circumstances without which the patient
would not have died. For example, a cancer patient dies and the immediate cause of death was heart
failure resulting from carcinomatosis. However, the original neoplasm site was colon. The sequence
would be malignant neoplasm resulting in carcinomatosis resulting in heart failure. In this example, the
heart failure was the final morbid event in the sequence, starting with cancer of the colon. The malignant
neoplasm of the colon is the condition to be coded as the underlying cause of death.
By the time the death certificate reaches you for coding, the health care practitioner or certifier
should have recorded:
 the sequence of morbid events leading to death
 the original cause of the sequence
Preferably the death certificate used should be the international form recommended by the WHO.
This has 2 parts.
Part I - is used for diseases related to the sequence of events leading directly to the death.
Part II - is used for unrelated conditions which have no direct connection with the events leading to death
but which, by their nature, contributed to death.
Part I of the form has 3 - 4 lines, depending on the local practice, to record the sequence of events leading to
death.
Where two or more conditions must be recorded, the certifying practitioner should record the sequence of
events leading to death. Each event in the sequence should be recorded on a separate line, in reverse order.
 The direct cause of death is entered on the first line
 The underlying cause of death is entered on the lowest used line
 Any intervening causes are entered on the lines between the first line and the lowest used line.
The completed certificate therefore contains the following information:
I(a) Direct cause
(b) Intervening Cause of (a)
(c) Intervening cause of (b)
(d) Originating cause of (c)
In terms of the previous example of heart failure, carcinomatosis and cancer of the colon, the completed
certificate would look like this:
I(a) Heart failure
(b) Carcinomatosis

2299
(c) Cancer of the colon
II-
There are two ways of classifying injuries:
 By their nature (chapter XIX)
 By the external cause resulting in the injury (chapter XX)
For mortality purposes it is the external cause that should be used for single cause coding and tabulating
underlying cause.
You should note that whilst most of the ICD is used for coding underlying cause of death, there are particular
sections and codes that should NOT be used for this purpose. For example asterisk codes should not be used
to classify underlying cause of death.
Selecting the underlying cause of death
The World Health Organization has defined a set of procedures or coding rules to be followed for coding the
underlying cause of death. This series of steps will be outlined in the following pages.
When coding, for each case the rules should be applied in a logical sequence beginning with the General
Principle.
General Principle:
When more than one condition is entered on the certificate, the condition entered alone on the lowest
used line of part I should be selectedonly if it could have given rise to all the conditions entered above
it.

Example:
I(a) Abscess of lung
(b) Lobar pneumonia
Select lobar pneumonia (J18.1) as the underlying cause as the lung abscess could have been the result of
the lobar pneumonia .
In about 25% of cases the General Principle cannot be applied for some reason. Rules 1, 2 and 3 then need to
be applied.
RRuullee 11
If the General Principle does not apply and there is a reported sequence terminating in the condition
first entered on the certificate, select the originating cause of this sequence.
If there is more than one sequence terminating in the condition mentioned first, select the originating
cause of the first-mentioned sequence.
In other words, Rule 1 applies when there is a reported sequence but the General Principle cannot be applied.
For example, rule 1 may be applied when there is more than one condition entered on
the lowest used line
Example:
I(a) Bronchopneumonia
(b) Cerebral infarction and hypertensive heart disease
Select cerebral infarction. There are two reported sequences terminating in the condition first entered
on the certificate; bronchopneumonia due to cerebral infarction, and bronchopneumonia due to
hypertensive heart disease. The originating cause of the first-mentioned sequence is selected.

3300
Rule 1 is also invoked if the single condition entered on the lowest used line on the certificate could not
have resulted in all of the conditions listed above.
Example:
I(a) Acute myocardial infarction
(b) Atherosclerotic heart disease
(c) Influenza
Select atherosclerotic heart disease. The reported sequence terminating in the condition first mentioned on
the certificate is acute myocardial infarction due to atherosclerotic heart disease. Influenza could not have
caused the atherosclerotic heart disease or the myocardial infarction.
If there is no logical sequence, Rule 2 should be applied.
RRuullee 22
If there is no reported sequence terminating in the condition first entered on the certificate, select this
first-mentioned condition.
Example:
I(a) Pernicious anaemia and gangrene of foot
(b) Atherosclerosis
Select pernicious anaemia (D51.0). There is no reported sequence terminating in the pernicious
anaemia, which is the first mentioned condition
In some cases there is a condition reported in Part I or II that has not been selected using the General rule or
Rule 1 or 2, but which could have obviously caused the other conditions on the certificate. In these cases rule
3 is applied.
RRuullee 33
If the condition selectedby the General Principle or by Rule 1 or Rule 2 is obviously a direct
consequence of another reported condition, whether in Part I or Part II, select this primary condition.
Example:
I(a) Bronchopneumonia
Secondary anaemia and chronic lymphatic leukaemia
Select chronic lymphatic leukaemia (C91.1). Bronchopneumonia, selected by the General Principle,
and secondary anaemia can both be considered direct sequels of chronic lymphatic leukaemia.
Some conditions are assumed to be direct consequences of another condition such as:
Burkitt’s tumour, Kaposi’s sarcoma, malignant neoplasms of lymphoid, Aaematopoietic and related tissue –
considered to be a direct consequence of HIV disease.
Any infection classifiable to Aoo-B19, B25-B49, B58-B64, B-99 or J12-J18 – considered as
direct consequence of HIV disease.
Rules for modification:
In some cases the underlying cause that has been selected using the above rules is not the most useful or
informative for public health or prevention purposes, e.g. senility or a general disease process such as
atherosclerosis. In such cases modification rules may need to be applied after the General Principle, Rule 1,
Rule 2 and Rule 3 have been applied.
There are 6 modification rules (A-F).

3311
RRuullee AA.. SSeenniilliittyy aanndd ootthheerr iillll--ddeeffiinneedd ccoonnddiittiioonnss
Where the selectedcause is ill-defined and a condition classified elsewhere is reported on the certificate,
reselect the cause of death as if the ill-defined condition had not been reported, except to take account
of that condition if it modifies the coding. The following conditions are considered ill-defined: I46.9
(Cardiac arrest, unspecified), I95.9 (Hypotension unspecified), I99 (Other and unspecified disorders of
circulatory system), J96.0 (Acute respiratory failure), J96.9 (Respiratory failure unspecified), P28.5
(Respiratory failure of newborn), R00-R94 or R96-R99 (Symptoms, sings and laboratory findings, not
elsewhere classified).Note that R95 (Sudden Infant Death Syndrome) is not regarded as ill-defined.
Example:
I(a) Senility and hypostatic pneumonia
(b) Rheumatoid arthritis
Code to rheumatoid arthritis(M06.9). Senility, selected by Rule 2, is ignored and the General Principle
applied.
RRuullee BB.. TTrriivviiaall ccoonnddiittiioonnss
Where the selectedcause is a trivial condition unlikely to cause death, and a more serious
condition (any condition except an ill-defined or another trivial condition) is reported,
reselect the underlying cause as if the trivial condition had not been reported. If the death
was the result of an adverse reaction to treatment of the trivial condition, select the adverse
reaction.
When a trivial condition is reported as causing any other condition, the trivial condition is
not discarded, i.e. Rule B is not applicable.
Example:
I(a) Dental caries
II Diabetes
Code to diabetes (E14.9). Dental caries, selected by the General Principle is ignored, as it
may be considered a trivial condition.
Example:
I(a) Septicaemia
(b) Impetigo
Code to impetigo (L01.0). The trivial condition selected by the General Principle is not
discarded since it is reported as the cause of another condition, in this case the cause of the
septicaemia.
RRuullee CC.. LLiinnkkaaggee
Where the selectedcause is linked by a provision in the classification or in the notes for use in
underlying cause mortality coding with one or more of the other conditions on the certificate, code the
combination.
Where the linkage provision is only for the combination of one condition specified as due to another,
code the combination only when the correct causal relationship is stated or can be inferred from
application of the selection rules.
Where a conflict in linkage occurs, link with the condition that would have been selectedif the cause
initially selectedhad not been reported. Make any further linkage that is applicable.
Example:
I(a) Intestinal obstruction
(b) Femoral hernia Code to femoral hernia with obstruction (K41.3).

3322
Example:
I(a) Acute myocardial infarction
(b) Atherosclerotic heart disease
(c) Influenza
Code to acute myocardial infarction (I21.9). Atherosclerotic heart disease, selected by Rule 1, links with
acute myocardial infarction
RRuullee DD.. SSppeecciiffiicciittyy
Where the selectedcause describes a condition in general terms and a term that provides more precise
information about the site or nature of this condition is reported on the certificate, prefer the more
informative term. This rule will often apply when the general term becomes an adjective qualifying the
more precise term.
Example:
I(a) Meningitis
(b) Tuberculosis
Code to tuberculous meningitis (A17.0). The conditions are stated in the correct causal relationship.
RRuullee EE.. EEaarrllyy aanndd llaattee ssttaaggeess ooff ddiisseeaassee
Where the selectedcause is an early stage of a disease and a more advanced stage of the same disease is
reported on the certificate, code to the more advanced stage. This rule does not apply to a "chronic"
form reported as due to an "acute" form unless the classification give special instructions to that effect.
Example:
I(a) Tertiary syphilis
(b) Primary syphilis
Code to tertiary syphilis (A52.9).
RRuullee FF.. SSeeqquueellaaee
Where the selectedcause is an early form of a condition for which the classification provides a separate
"Sequelae of …" category, and there is evidence that death occurred from residual effects of this
condition rather than from those of its active phase, code to the appropriate "Sequelae of …" category.
Example:
I(a) Pulmonary fibrosis
(b) Old pulmonary tuberculosis
Code to sequelae of respiratory tuberculosis (B90.9)..
Duration
The stated time factor (or duration) in a sequence should be considered. This is important when you are
considering whether one condition was caused by another. However, this is often a poorly completed item on
a death certificate and this should be taken into account when interpreting entries.
Nature of injury
Although the external cause of an injury or injuries should be coded as the underlying cause of death, WHO
also recommends that the nature of injury is also classified. When more than one kind of injury to a single
body region is recorded, and there is no clear indication as to which caused death, you must apply the General
Principle and selection rules in the usual way. This relates to categories:
S00-S99 T08-T35 T66-T79
Malignancy:

3333
When malignancy is given as the underlying cause of death three factors must be taken into consideration
when assigning a code. These are the:
Site
Morphology
Behaviour of the neoplasm. If there are 3 factors associated with recording malignant neoplasm as a cause
of death then it is not surprising that problems can arise with the way the certificate has been completed.
You may be coding a certificate where malignancy is implied but not explicitly stated. Metastases or
secondaries are recorded but malignancy itself is not mentioned.
Example:
I(a) Metastatic involvement of lymph node
(b) Carcinoma-in-situ of breast
Code to malignant neoplasm of breast (C50.9).
If a neoplasm has given rise to metastases or secondaries it means that the neoplasm is malignant. Sometimes
the site of a neoplasm may be stated imprecisely. You may find sites prefixed with words like: peri-, para-,
pre-, supra-, or infra-.
Example:
I(a) Fibrosarcoma in the region of the leg
Code to malignant neoplasm of connective and soft tissue of lower limb (C49.2
You should not assume the site of a malignancy from other conditions reported on the certificate if the site of
the primary neoplasm is not mentioned.
Example:
I(a) Obstruction of intestine
(b) Carcinoma
Code to malignant neoplasm without specification of site (C80).
When a malignancy is entered on the certificate and the primary site is indicated, you should always select the
primary site as the underlying cause of death and not any recorded metastatic sites. Do this regardless of the
position of the primary site on the certificate.
There are 3 ways the site may be indicated:
when one site is specified as primary in either part I or part II
when other sites may be described as secondary or metastatic
when the morphology itself may indicate a primary malignancy.
You may encounter cases where the primary site is stated to be unknown. In such cases, do not make any
assumptions about the primary site from any other conditions, which are specified. Instead, you should look at
the morphology of the neoplasm or code to C80 Malignant neoplasm without specification of site. In some
cases of malignancy there may be more than one primary site. [ If the sites are not in the same organ system
and there is no indication that any is primary or secondary, code to malignant neoplasm of independent
(primary) multiple sites (C97)]. A special category has been created for these cases at C97 Malignant
neoplasm of independent (primary) multiple sites. A malignancy may spread to another site. This is called
metastasis.
The adjective ‘metastatic’ is frequently used ambiguously - sometimes meaning a secondary FROM a primary

3344
elsewhere and sometimes meaning a primary which has given rise TO metastases. It is very difficult to
resolve this situation as there are no specific rules and usage varies between countries and language.
In some cases multiple sites may be recorded with no indication as to which is the primary site. You may find
that an infectious disease has been given as a consequence of a malignancy. This is an acceptable sequence.
Malignant neoplasm can also cause certain types of circulatory diseases. The underlying cause of death will
be malignancy.

3355
Chapter specific notes

3366
Certain Infectious and Parasitic Diseases (ChapterI)
This chapter includes diseases generally recognised as communicable or transmissible.
Important points for Chapter I
Categories range from A00 to B99. In fact, this is one of the largest chapters in ICD-10.
171 of the 200 available categories have been allocated.
The chapter is divided into 21 blocks.
The use of the modifier “Certain” in the title indicates that some infectious and parasitic diseases are
classified elsewhere – it is necessary to carefully read inclusion and exclusion notes.
Chapter I has five exclusions listed at chapter level.
It should also be noted that there are some exceptions to the exclusions - they are related to obstetrical and
neonatal tetanus, congenital syphilis, perinatal gonococcal information and obstetric and perinatal HIV
disease -which are included in Chapter I.
A rule exists in relation to the presumption of infectious or noninfectious origin of gastroenteritis or
diarrhoea dependent on the country in which the patient contracted the condition. This rule only applies where
there is no specification as to whether the diarrhoea is infectious or non-infectious. If the diarrhoea is
presumed to be non-infectious, it should be coded to K52.9 (in the Diseases of Digestive System chapter).
If the diarrhoea is presumed infectious, it is coded to Chapter I. The decision about which code to use should
be made by each individual country – but be aware that this rule only applies to cases which are not specified
as infectious or non-infectious.
When coding tuberculosis, categories A15-A16 identify whether the tuberculosis was confirmed and what
method was used for the confirmation e.g. sputum microscopy, chest x-ray.
Block B20-B23 has a note at the beginning concerning the use of the fourth character subcategory. The
categories have been provided for optional use when it is not possible to multiple code.
Block B50- B64 provides guidance by the use of exclusion and inclusion notes on how mixed plasmodium
infections are to be coded.
B90-B94 codes are to be used when the condition being treated is a sequelae of an infectious disease.
B95-B97 is a block of additional codes that enables infectious organisms to be recorded as the cause of
conditions primarily classified to other chapters. These codes should never be used for primary/main
condition coding; they are additional or supplementary codes.

3377
Neoplasms (ChapterII)
This chapter covers the coding of all neoplastic tumours, both malignant and benign and also cases where
there is some uncertainty about the behaviour of a tumour.
Important points for Chapter II
Categories range from C00 to D48.
The chapter is divided into 7 blocks, with the block of primary malignancy codes subdivided into 12 further
sub-blocks.
It is especially important when coding neoplasm to use both Volume 1 and Volume 3 in identifying the
correct set of codes
The three specific aspects to take into account when coding neoplasm are:
the site of the tumour
the nature of the tumour (also known as the morphology or histological type),
and the behavior of the tumour.
Chapter II is organised by tumour site and grouped in terms of the behaviour of neoplasm
The behaviour may be coded using the morphology codes – further information is provided
below.
D10-D36 /0 benign neoplasms
D37-D48 /1 neoplasms of uncertain and unknown behaviour
D00-D07 /2 in situ neoplasms
C00-C75 & /3 malignant neoplasms, stated or
C81-C97 presumed to be primary lesions
C76-C80 /6 malignant neoplasms, stated or presumed to be secondary lesions.
Morphology describes the structure and type of cells or tissues as seen under the microscope. The tissue of
origin and the type of cells that make up a malignant neoplasm often determine the expected rate of growth,
the severity and the type of treatment given. Morphology is described by an additional coding system found in
the ICD-10. The morphology code numbers are 6 digits long, including the prefix “M”.

Behaviour indicates how the tumour will behave ie. malignant (primary or secondary), in situ, of uncertain
or unknown behaviour or benign. The behaviour is the final digit of the morphology code. Sometimes the
ICD-10 Index indicates the behaviour of a neoplasm (because the histological type always acts in a certain
pattern) but, when coding, if the clinician overrides the expected behaviour then accept the override in that
particular case e.g. adenoma is usually benign, but if clinician documents a case as malignant adenoma,
code the case as such. The behaviour code is changed from the expected /0 to /3 to indicate malignant
primary.
The Table of Neoplasms is included in Volume 3 and includes the Chapter II codes for each anatomical site
of tumour. For each site, there are five possible code numbers according to the behaviour of the tumour. If the
diagnosis you are coding does not describe the behaviour of the tumour, you should look up the morphology
description in the rest of the Index for guidance as to how the tumour should be coded. E.g. Mesonephroma -
see Neoplasm, malignant. You would therefore use the code for malignant primary tumour or malignant
secondary tumour, depending on the diagnosis.
In Chapter II, the 4th digit .9 is for unspecified site and .8 is for overlapping lesions of contiguous sites.

3388
At the back of the Tabular List, is a Table of Morphology of Neoplasm. This table consists of
a comprehensive but not exhaustive list of morphological types of neoplasm; the coder should be aware that if
the behaviour type being sought is not listed with the histological type then the final digit can be changed (if
this is clinically correct). For example, many malignant neoplasm are listed only with the morphology code
for the primary lesion; if a secondary lesion needs to be coded, change the final “3” to “6” and the code is
correct.
Example:
To find the correct site and morphology codes for a female patient suffering from lobular carcinoma
arising in the lower outer quadrant of the left breast.
Step 1:
Look up the lead term, carcinoma, in the Alphabetical Index.
Carcinoma
- lobular (infiltrating) (M8520/3)
- - specified site - see Neoplasm, malignant
Step 2:
The morphology you are given is M8520/3. Confirm that the behaviour (/3) is appropriate for the tumour
being described. /3 indicates a primary malignancy and is therefore appropriate for this case because our
diagnosis specifies that the tumour arose from the breast.
Step 3:
Check the morphology (M8520) in the Table of Morphology of Neoplasms in Volume 1. The morphology
is correct for this case.
Step 4:
Look up the Table of Neoplasm in volume 3. Use the alphabetic listing of anatomical sites to find the
entry for ‘breast’. Note the subdivisions under the lead term for different parts of the breast. Find the
section for the lower outer quadrant.
Step 5:
Find the code in the column Malignant primary tumour by looking across the row for lower outer
quadrant of the breast. We are told that the tumour arose in the patient’s breast; it is therefore a primary
tumour and not a metastasis. The correct site or Chapter II code is therefore C50.5.
Step 6:
Confirm your code selection in Volume 1 of the ICD-10. Check whether there are any relevant
exclusion notes.
Step 7:
The codes for this case are C50.5, M8520/3

3399
DiseasesofThe BloodAnd Blood Forming Organs
And Certain Disorders Involving The Immune Mechanism
(CHAPTER III)
Important points for Chapter III
Categories range from D50 to D89.

34 of the available 40 categories have been used.

The chapter is divided into 6 blocks, 3 of which relate to anaemia.

There are 2 asterisk categories in this chapter.

Note that the exclusions remind the coder that HIV disease is coded to Chapter I (see Chapter I- B20-B24).

4400
Endocrine, Nutritional and Metabolic Disorders (ChapterIV)
This chapter includes disorders of the endocrine glands, nutritional disorders and metabolic disorders.
Important points for Chapter IV
Categories in this chapter range from E00 to E90.
73 of the available 91 categories have been allocated.
There are 2 asterisk categories.

Included are disorders of the endocrine glands (E00-E35), nutritional disorders (E40-E64) and metabolic
disorders (E65-E90).

The disorders of endocrine glands are grouped anatomically.

Some of the codes in this chapter can be used as additional codes to indicate the functional activity of
neoplasm.

An additional code can be assigned to indicate presence of mental retardation associated with iodine
deficiency. The ‘Use additional code’ instruction is utilised.

E10-E14, the block on diabetes mellitus, uses insulin-dependent diabetes mellitus (IDDM) and non-insulin-
dependent diabetes mellitus (NIDDM) as preferred terminology, although it does include reference to Types I
and II diabetes mellitus (among others) within the categories. Type I diabetes is equivalent to IDDM, Type II
is equivalent to NIDDM.

Insulin dependent diabetes mellitus, non-insulin dependent diabetes mellitus and malnutrition related
varieties of diabetes are identified at the 3 character level and complications of the diabetes are identified at
the fourth character level.
Example:
Non-insulin dependent diabetes mellitus (NIDDM) with diabetic nephropathy. The correct
code would be:

4411
Mental and Behavioural Disorders (ChapterV)
This chapter deals with mental and behavioural disorders of all origins.
Important points for Chapter V
Categories range from F00 to F99.
Of the 100 available categories, 78 have been allocated.
There are 2 asterisk categories, relating to dementia in Alzheimer’s disease and in other diseases classified
elsewhere.

Each category is prefaced by a comprehensive description of the disorders it contains.

There is emphasis on behavioural disorders as well as mental disorders.

Block F00-F09 covers organic mental disorder. That is, those disorders resulting from a physical cause e.g.
dementia in Alzheimer’s disease.

Block F10-F19 covers disorders due to the use of psychoactive or other substances. The third character
indicates the substance involved and the fourth character indicates the clinical state of the patient.

4422
DiseasesofThe Nervous System (Chapter VI)
This chapter provides codes for diseases and disorders of the nervous system.
Important points for Chapter VI

The categories in this chapter range from G00 to G99.

67 of the 100 available categories have been used.


The chapter relates to both the central and peripheral nervous systems.

G00-G09 classifies disease where the nerve tissue is attacked by different organisms. All
meningoencephalitis and meningomyelitis are included here, as are encephalitis, myelitis and
encephalomyelitis.
G40-G47 is for the coding of disorders that occur episodically, e.g. epilepsy, migraines and sleep disorders.

The exclusion note at the beginning of block G50-G59 should be clearly understood. Current injuries to
nerves should be classified under injury of the particular body region. There are a number of exclusions
within this block which direct the coder to Chapter XIII, Diseases of the Musculoskeletal System and
Connective Tissue.

4433
DiseasesofThe Eye and Adnexa (Chapter VII)
This is chapter deals exclusively with diseases of the eye and its adnexa.
Important points for Chapter VII
The categories in this chapter range from H00 to H59.

Note the use of additional/optional codes for H40.3, H40.4, H40.5 and H40.6 to identify the cause of
glaucoma.

H54 blindness and low vision is an important category, which has a table detailing impairment categories

4444
DiseasesofThe Ear and MastoidProcess(ChapterVIII)
This chapter deals exclusively with diseases of the ear and mastoid process.
Important points for Chapter VIII
The categories in this chapter range from H60 to H95.

The blocks are divided anatomically: external ear, middle ear and mastoid, and inner ear. The final block
(H90-H95) contains codes relating to hearing loss, symptom-type conditions, disorders of the acoustic nerve
and postprocedural problems.

H90 classifies conductive and sensorineural hearing loss by unilateral and bilateral impairment.

4455
Diseasesofthe Circulatory System (Chapter IX)
Chapter IX covers the organs and systems involved in the circulation of blood and lymph, but not
the blood itself. Blood is covered in Chapter III.
Important points for Chapter IX

Categories I00 to I99 make up this chapter.

Of the 100 categories available, 77 have been allocated.



Care should be taken with this chapter because the prefix "I" looks like a "1", when written or typed, and
this can be confusing.

I05-I09 includes most valvular disease whether they are specified as rheumatic or not. Be aware of the
exceptions though: valvular diseases of the aortic valve are classified to this block only if they are specified as
rheumatic.

I10-I15 Hypertensive disorders have no distinction between malignant and benign types as was the case in
ICD-9.

I20-I25 has a note which provides guidance for coders in establishing duration of ischaemic heart diseases.
This makes a distinction between morbidity and mortality coding in the application of the codes

4466
Diseasesofthe RespiratorySystem (Chapter X)
Chapter X is concerned with diseases and disorders of the respiratory organs including those
caused by infection and some external agents, such as in occupational exposure.
Important points for Chapter X
This chapter includes categories J00 to J99.
There are 3 asterisk categories in the chapter.

When a respiratory condition is described as occurring in more than one site and the condition is not
specified in the Index, it should be classified to the lower anatomical site eg. tracheobronchitis is coded to
bronchitis (J40), not tracheitis plus bronchitis (J04.1 + J40). This coding rule is to be found at the beginning of
the chapter. In practice, however, the Index includes many of the possible combinations (eg.
pharyngotracheitis (J06.8), laryngotracheobronchitis (J40), tracheobronchopneumonitis (J12-J18)) and directs
the coder to the appropriate code.

The section concerning acute upper respiratory infections (J00-J06) is arranged anatomically, from nose
down to larynx.

Bronchitis not specified as acute or chronic is assumed to be acute if the person is under 15 years and is
coded as J20.9.

Abscess of lung with pneumonia where the causative organism is not specified, is coded to J85.1. If the
causative organism is specified, the condition is classified to block J10-J16.

Pleurisy without mention of effusion or current tuberculosis is classified to the symptoms chapter (R09.1).
Pleurisy with pleural effusion is classified to J90 Pleural effusion, not elsewhere classified.

4477
DiseasesofDigestive System(Chapter XI)
Chapter XI involves diseases and disorders of the alimentary tract or digestive system.
Important points for Chapter XI
Categories K00 to K93 comprise this chapter.



Except for block K40-K46 (Hernias), the codes in the range K00-K63 are arranged anatomically from
mouth to anus. These are then followed by blocks concerning disorders of the other main organs associated
with digestion.


Block K25-K29 has a fourth character subdivision to identify if haemorrhage or perforation occurred.

For block K40-K46 there is a note which states that if a hernia is described as both gangrenous and
obstructed, only the gangrene need be coded (specified at 4th digit level). This is because the gangrene is the
result of the obstruction.

Block K57 Diverticular disease of the intestine includes diverticulosis, diverticulum and diverticulitis. The
fourth character level is used to specify if there is perforation or an abscess present.

4488
Diseasesofthe Skin And Subcutaneous Tissue (ChapterXII)
This chapter covers diseases of the skin and subcutaneous tissue.
Important points for Chapter XII
Categories range from L00 to L99.


There are 10 exclusions listed at the start of the chapter.

8 of the exclusions listed are at chapter level, one at block level and at one at code level.

There are 8 blocks.


This chapter has many exclusions and inclusions, listed at the beginning of many of the blocks and
categories, in addition to those at the start of the chapter. The exclusion notes identify elements of codes that
are classified elsewhere.

The terms dermatitis and eczema are used synonymously and interchangeably.

Contact dermatitis is classified according to whether it is allergic, irritant or unspecified. The three
categories do not have the same fourth character subdivisions, so care must be taken when assigning codes.
Take special note of the exclusions and cross references within these codes.
L55 sunburn is classified according to the depth of skin which is affected:
First degree/erythema - affecting epidermis only
Second degree/partial thickness - affecting both epidermis and dermis causing possible blistering
Third degree/ full thickness - affecting epidermis, dermis and subcutaneous layers, usually causing
extensive damage.

4499
Diseasesofthe MusculoskeletalSystem& Connective Tissue
(Chapter XIII)
This chapter covers diseases and conditions relating to the spine, joint, muscles and connective
tissue of the body. It also covers deformities acquired after birth.
important points for Chapter XIII
Categories range from M00 to M99.


12 of the categories have asterisk codes.

The Site of Musculoskeletal Involvement is an additional optional subclassification (located at the
beginning of the chapter) provided to indicate the site of involvement of a condition where this is appropriate.
Valid fifth digits are indicated in square brackets [ ] after each code to which they apply. The use of these
optional codes is a matter for decision by each country as they are not a mandatory part of the codes.

Supplementary classifications for optional use are also given for the following conditions:
M23 Internal derangement of knee
M40-M54 Dorsopathies (except M50 & M51)
M99 Biomechanical lesions NEC.

There are 6 major blocks in this chapter, 4 of which are broken down into smaller blocks making 15 blocks
in total.

M00-M03 begins with a note explaining an important distinction that is made between the causes (direct or
indirect aetiological relationship) of the various disorders. This is the basis of the classification used for this
block.

M15-M19 Arthrosis. The term arthrosis is synonymous with osteoarthritis and osteoarthrosis.

M40-M54 Dorsopathies, has a second supplementary subclassification to indicate the site of involvement.
This is set for optional use for all categories in this block, except M50 and M51.

5500
Diseasesofthe Genitourinary System(Chapter XIV)
This chapter comprises the urinary system and the male and female reproductive systems.
Important points for Chapter XIV

Categories range from N00 to N99.


9 of the categories have asterisk codes.

Chapter XVI has 8 exclusions listed at chapter level.


N00-N08 Glomerular disease The three character categories relate to clinical syndromes (e.g. chronic
nephrotic syndrome) and the fourth characters allow the coding of morphological changes (e.g. focal and
segmental glomerular lesions).

An additional code from N17-N19 Renal Failure may be used with a code from another chapter, if desired,
to identify the presence of renal failure.

N70-N77 Inflammatory disease of female pelvic organs consists of eight categories organized to follow the
structure of the female reproductive system, starting with the ovary and fallopian
tube.

Dysplasia of the cervix, vagina and vulva are classified by severity in categories N87, N89 and N90

5511
Pregnancy, Childbirth and the Puerperium (Chapter XV)
This chapter covers disorders and complications that arise during pregnancy, childbirth and the
puerperium.
Important points for Chapter XV
Coders should be very careful in distinguishing the letter “O” from the number “0” in this
chapter.

Categories range from O00 to O99.
The chapter starts with a list of 8 exclusions.
The first 3 blocks are mostly concerned with pregnancy.
Inclusion and exclusions are found at the beginning of each block or category.
Throughout this chapter there are quite a few notes, some of which refer you to either morbidity or mortality
guidelines in Volume 2. Make sure you read these before you assign a code from this chapter.

O00-O08 Pregnancy with abortive outcome, covers all abortions, but excludes continuing pregnancy in
multiple gestation after abortion of one fetus or more. Complications related to abortions are specified by
fourth character subdivisions. Category O08 also has a note to indicate that this category is primarily for
morbidity coding.

O20-O29 Other maternal disorders predominantly related to pregnancy, contains many varied
conditions associated with pregnancy, e.g.:
 O20 Haemorrhage in early pregnancy
 O21 Excessive vomiting in pregnancy
 O22 Venous complication in pregnancy

O60-O75 Complications of Labour and delivery is structured to follow the progress of labour.

O80-O84 Delivery, is a block which allows for single deliveries to be classified at the three character level.
The codes are primarily for morbidity purposes. Guidelines are provided in Volume 2 and should be referred
to before assigning codes from this block.

O85-O92 covers the puerperium and includes problems with lactation.

O95-O99 includes maternal health.

There are time limits associated with O96 Death from any obstetric cause occurring more than 42 days but
less than 1 year after delivery, and O97 Death from sequelae of direct obstetric cause (one year or more).


5522
Certain Conditions Originating in the PerinatalPeriod(Chapter XVI)
This chapter is concerned with conditions affecting the fetus and the newborn baby, originating in
the perinatal period.
Important points for Chapter XVI
Categories range from P00 to P96.
Of the 100 available categories 59 have been allocated.
There is one inclusion at the beginning of this chapter, and 5 exclusions.
For disorders related to length of gestation and foetal growth, birth weight takes priority over gestational
age as evidence of maturity of the baby. This is because birth weight is a more objective measure than
gestational age, which might be miscalculated. For example, P07
Disorders related to short gestation and low birth weight, not elsewhere classified, has a note at the beginning
of the category to give guidance on the assignment of this code if both birth weight and gestational age are
specified.

P10-P15 birth trauma is classified to six categories which are arranged according to the physical effect of
the injury, e.g. P10.2 Intraventricular haemorrhage due to birth injury.

P35-P39 Infections specific to the perinatal period, includes only congenital infections and parasitic disease
and those infections acquired in utero or which are present at birth. There are some exceptions to this and
these are clearly noted in the appropriate category.


5533
CongenitalMalformations, Deformations
and Chromosomal Abnormalities (Chapter XVII)
This chapter covers congenital malformations, deformations and chromosomal anomalies.
Important points for Chapter XVII
Categories range from Q00 to Q99.
No asterisk categories are found in this chapter.

5544
Symptoms, Signs And Abnormal Clinical & Laboratory Findings, Not Elsewhere
Classified(Chapter XVIII)
This chapter covers:
symptoms
signs
abnormal results of clinical or other investigative procedures
and
ill defined conditions regarding which no diagnosis classifiable elsewhere is recorded
Important points for Chapter XVIII
Categories range from R00 to R99
90 of the available 100 categories have been allocated
A group has been created for symptoms involving cognition perception, emotional state and behaviour at
R40 -R46 and speech and voice at R47-R49
Blocks are listed after 2 exclusions for the chapter
Any exclusions from a block or category are given and the category or subcategory to which the exclusion
belongs is always specified.
There are no asterisk categories in this chapter

The Alphabetical Index (Volume 2) should always be used to clarify which signs and symptoms are to be
assigned to chapter XVIII and which to other chapters.

R10 Abdominal and pelvic pain is subdivided according to the site of the pain, e.g. Pain localised to the
upper abdomen.

R47-R49 classifies symptoms and signs involving speech and voice, and conditions such as speech
disturbance not elsewhere classified, and voice disturbance.

R70-R94 deals with abnormal findings. These codes are to be used when no clear diagnosis has been given
and a person is having follow-up of an examination indicating abnormal findings.

R95-R99 Ill-defined and unknown causes of mortality, as the titles suggest, are to be used for mortality
coding. They are only to be used if no other specific code can be assigned

5555
Injury, Poisoning And Certain Other ConsequencesOfExternal Causes (ChapterXix)
& External Causes Of Morbidity And Mortality (Chapter XX)
These two chapters cover injury, poisoning and certain other consequences of external causes and the
classification of environmental events and circumstances as the cause of injury, poisoning and other adverse
effects.
The external cause concept
The use of Chapter XX codes permits the classification of environmental events, circumstances and
conditions as the cause of injury, poisoning and other adverse effects. The use of Chapter XX codes along
with Chapter XIX codes provides additional information of particular concern to industrial medicine, national
safety programs and national health agencies. Injury prevention programs are often based on the information
coded to this Chapter.

When multiple coding, a Chapter XX code should always be assigned with a Chapter XIX code. That is, a
code describing how the injury(s) occurred as well as the injury code(s) will be assigned. When coding
underlying cause of death, the code for the external cause takes priority. Conversely, when coding morbidity
records, the main condition will be the nature of the most severe injury.
Important points for Chapter XIX
Categories range from S00 to T98.
Of the 199 available categories 195 have been allocated.
Blocks S00-S99, at the three-character level are classified by site of injury, e.g. head, arms.
The fourth character level indicates the type of injury that occurred, e.g. fracture, open wound.
Codes in the range T00-T98 are used to code all other trauma, e.g. burns, complications of
surgery, poisonings.
When multiple coding, all injuries should be coded, avoid the use of 'multiple' type codes. Multiple codes
are useful for single condition coding. eg T06.- can be used to code fractures of multiple regions of upper
limb(s) in association with lower limb(s).
Important points for Chapter XX
Four letters of the alphabet - V,W,X.and Y - have been assigned to this chapter, making it the largest in
ICD-10.
Categories range from V01 to Y98.
Of the 400 available categories 372 have been used.
8 major blocks

The Chapter includes Place of occurrence codes, which are fourth character subdivisions used to identify
the place where an injury occurred. They are to be used with categories W00 - Y34 (except Y06 and Y07).
.0 Home
.1 Residential institution
.2 School, other institution, public administrative area
.3 Sports and athletics area
.4 Street and highway
.5 Trade and Service area
.6 Industrial and construction area
.7 Farm

5566
.8 Other specified places
.9 Unspecified place

An Activity code is also provided for optional use in a supplementary character position with categories
V01-Y34 to indicate the activity the injured person was involved in at the time of the injury. This code should
not be confused with, or be used instead of, the place of occurrence code.
0 while engaged in sports activity
1 while engaged in leisure activity
2 while working for income
3 while engaged in other types of work
4 while resting, sleeping, eating or engaging in other vital activities
8 while engaged in other specified activities
9 while engaged in unspecified activities

Chapter XX codes can also be assigned with codes from Chapter I-XVII to identify the external cause of a
condition, e.g. dermatitis due to solvents.

Chapter XX codes are never assigned as the main condition code for morbidity coding. For mortality coding
the Chapter XX code is the code assigned for the underlying cause of death.

V01-V79 Motor vehicle transport accidents, are classified at the three character level by the mode of
transport of the injured person and at the fourth character level according to the position of the person in the
motor vehicle.
X60-X80 Intentional self harm, are incidents determined as being suicide or self-inflicted injuries.

The Table of Drugs and Chemicals, found at the back of the Alphabetical Index, guides the coder to the
correct codes to describe poisonings by drugs and chemicals. To use the Table, first of all look up the name of
the drug in the alphabetical list. The first column indicates the nature of injury code from Chapter XIX that is
appropriate for the specific drug. Check the Tabular list to confirm this code selection. The other four columns
in the Table give the External Cause codes to describe the circumstances of the poisoning e.g. accidental,
intentional self-harm, undetermined intent and adverse effect in therapeutic use. Select the appropriate code
and confirm it in the Tabular list. Add the Place of Occurrence and/or Activity codes as required.

Y10-Y34 Event of undetermined intent, includes occurrences where it is not clear whether the person was
accidentally injured or the injury was purposely inflicted.

Terms to be aware of when searching the index for the external cause are ‘exposure’ and ‘contact’ if the
person comes in contact with an object or instrument; or is exposed to an element.

5577
Factors Influencing Health Status and Contactwith Health Services
(CHAPTER XXI)
This chapter is for use for occasions when circumstances other than a disease, injury or external cause
classifiable to categories A00-Y89 are recorded as “diagnoses” or “problems”.
Important points for Chapter XXI
Categories range from Z00 to Z99
A code for asymptomatic HIV is provided in this chapter.
Codes for contact with or exposure to HIV infection are also part of Chapter XXI.

Z00-Z13 Persons encountering health services for examination and investigation, has many exclusions
throughout the block, both to other categories within the block and other categories outside of the block. For
example Z02 and Z09 have exclusions to categories within this block as well as exclusions to other categories
within this chapter.

Z30-Z39 Person encountering health services in circumstances related to, covers all aspects of reproduction,
including contraceptive management, procreative management and pregnancy and antenatal care. Of
particular note is the use of Z37 Outcome of delivery, which can be used as an additional code to identify the
outcome of delivery on the mother's record. Z38 Liveborn infants, according to place of birth is used to code
health infants who are occupying a cot, but are not sick.

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