labratory tests.pptx

Common laboratory tests…..
IV-Hematology
1

Definition
 Hematology includes the study of blood cells and
coagulation.
 It encompasses;
 analyses of the concentration, structure, and function of
cells in blood;
 their precursors in the bone marrow;
 the chemical constituents of plasma or serum intimately
linked with blood cell structure and function; and
 the function of platelets and proteins involved in blood
coagulation.
2

• There are several different hematologic cell types that originate
from the hematopoietic stem cell.
• Each cell line has a defined role and unique contribution to the
overall homeostatic process, and may be found in the bone
marrow, lymph system,or blood.
• Each cell line has a defined role and unique contribution to the
overall homeostatic process.
• Typically, routine clinical laboratory testing involves measuring
concentrations of mature myeloid cells found in the blood.
3

Hematology
• Stem cells are young cells
• All blood cells start as stem cells
• They get “drafted” as RBCs, WBCs or
platelets depending on the body’s needs
5

Case
• You are rounding on an internal medicine with the
ICU team. When preparing for rounds, note that
there was a new admission last night – an
Olympic bicyclist who was struck by a car. Begin
reviewing the patient’s laboratory data in
preparation for rounds.
• On admissision to the hospital last night, patient
X had the following CBC:
7

Cont’d
• WBC: 7,200 cells/mm3
• RBC: 3.7 x 10^ 6 cells/mm3
• Hgb: 10 g/dl
• Hct: 30%
• MCV: 92 microM3/cell
• MCH: 30 pg/cells
• MCHC: 36 g/dl
8

Questions
 What do the above abbreviations represent?
 Which of the laboratory values are abnormal?
 What type of anemia is present?
 What is the most likely cause of the anemia in this
patient?
 In addition to the CBC, what other laboratory tests
were most likely ordered for this patient upon
admission to the hospital?
9

Cont’d
• Several days later the patient begins to spike fever. A CBC, chest x-
ray, UA and blood and urine cultures are done to look for possible
sources of infection. The CBC and UA results are as follows.
– CBC: with differential
– WBC: 17,900
• Segs: 65%
• Bands: 10%
• Lymphocytes: 17%
• Monocytes: 5%
• Eosinophils: 2%
– RBC: 4.2 X 10E6 cells/mm3
– Hgb 14 g/dl
– Hct: 42%
10

Cont’d
Urinalysis:
• Urine color: straw, cloudy
• SG: 1.010
• pH: 7.2
• Protein: trace
• Glucose: negative
• Ketones: negative
• Blood: trace
• Bilirubin: zero
• Leukocyte esterase: positive (Mane 1 marK)
• Nitrites: positive
11

Questions
• What abnormalities are notes in the CBC?
• What is left shift and what does it indicate?
Is a left shift present?
• What abnormalities are noted on the UA?
• What is the most likely cause of these
abnormalities?
12

CBC
A group of tests used for basic screening purposes.
 Uses:
• Enumeration of the cellular elements of the blood,
• Measurement of RBC indices, and
• determination of cell morphology
The results can provide valuable information about
overall health of the patient and the patient’s
response to disease and treatment.
 CBC can be indicated both for diagnostic and monitoring
13

CBC Cont’d
Diagnostic indications, to:
 Detect hematologic disorder, neoplasm, leukemia, or
immunologic abnormality,
 Determine the presence of hereditary hematologic
abnormality
 Evaluate known or suspected anemia and related
treatment
 Provide screening as part of a general physical
examination, especially on admission to a health care
facility or before surgery,???
14

CBC Cont’d
Monitoring indications, to:
 Monitor fluid imbalances or treatment for fluid
imbalances
 Monitor hematologic status during pregnancy
 Monitor progression of non-hematologic disorders,
such as COPD, malabsorption syndromes, cancer,
and renal disease
 Monitor response to chemotherapy and evaluate
undesired reactions to drugs that may cause blood
dyscrasias 15

Introduction
• The complete blood count (CBC) is one of the most commonly ordered
clinical laboratory tests.
• Main parameters measured:
• Red blood cell data
– Total red blood cell count (RBC)
– Hemoglobin (Hgb)
– Hematocrit (Hct)
– Red blood cell indices(MCV, MCH, MCHC)
– Erythrocyte Sedimentation Rate(ESR)
• White blood cell data
– Total white blood cell (leukocyte) count (WBC)
– A white blood cell count differential may also be ordered
• Platelet Count (PLT)
16

Hemoglobin
• The hemoglobin concentration is a measure of the
amount of Hgb in the peripheral blood, which
reflects the number of red blood cells in the blood
– Hgb constitutes over 90% of the red blood cells
• Decrease in Hgb concentration = anemia
• Increase in Hgb concentration = polycythemia
• Normal range
– Male: 14 – 18 g/dl
– Female 12 – 16 g/dl.
17

Hgb
• Hgb is the oxygen-carrying compound found
in the RBCs.
– Hgb level is a direct indicator of the oxygen-
carrying capacity of the blood
• Adaptation to high altitudes, extreme
exercise, and pulmonary conditions may
cause variations in hemoglobin values
18

Hgb- Clinical Significance
• Increased hemoglobin:
– Increased in diseases such as chronic obstructive lung
disease, polycythemia vera .
– May also be increased in
• Chronic smokers; athletes (regular vigorous exercise ): high
Landers(live at high altitudes)
• Decreased hemoglobin:
– Decreased in anemia of all types, particularly iron
deficiency anemia.
– Hgb is also reduced in blood loss, hemolysis, pregnancy,
fluid replacement or increased fluid intake
19

Hematocrit
• Hematocrit is a measure of the percentage of the
total blood volume that is made up by the red
blood cells
• The hematocrit can be determined directly by
centrifugation (“spun hematocrit”)
– The height of the red blood cell column is measured
and compared to the column of the whole blood
• Normal Range
– Male: 39 – 50%
– Female: 33 – 45% 20

Hct
• Hct describes the volume of blood that is occupied by RBCs.
• Expressed as a percentage of total blood volume.
• Rule of thumb
– Hct = 3 x Hgb
– Hgb= 3 x RBC
 Useful to detect laboratory error in measuring the Hb,
HCT, and RBC count
NB: Rule of Three applies only for normocytic,
normochromic cells!
21

Centrifuged blood (normal)
22
Plasma
Buffy coat (WBCs and Platelets)
Red blood cells
Normal Hct in
adult males
40-54%
Normal Hct in
adult females
34-51%

Centrifuged blood (adult male or female)
What is your diagnosis?
23
Plasma
Buffy coat
RBCs
Anemia – there is a low percentage of RBCs
(low hematocrit)

Hct- Clinical Significance
• Increase in Hct
– chronic obstructive lung disease and individuals who live at high
altitudes
– Also seen in dehydration
– hemoconcentration,
– polycythemia vera, or polycythemia secondaryto chronic hypoxia.
• Decrease hematocrit
– All types of anemias, blood loss, hemolysis, pregnancy, leukemia
– the bone marrow suppressant effects of drugs,
– chronic diseases,
– genetic alterations in RBC morphology
25

RBC count or Erythrocyte count
• Normal range:
– Male: 4.2 – 5.9 x 10e6 cells/mm
– Female: 3.5 – 5.5 x 10e6 cells/mm
• RBCs are produced in the bone marrow.
• Released into systemic circulation to transport oxygen
from the lungs to the body tissues.
• After circulating for a life span of ~120 days, the RBCs
are cleared by the reticuloendothelial system.
• RBC count is the actual amount of RBCs per unit of
blood.
26

RBC- Clinical Significance
Increased RBCs (Erythrocytosis)
are associated with high altitudes, strenuous
exercise and with specific disease conditions:
 Polycythemia vera
 Bone marrow failure
 Anxiety or stress
 Dehydration with hemoconcentration
 Erythremic erythrocytosis
 COPD with hypoxia and secondary polycythemia
27

RBC- Clinical Significance
 Decreased RBCs:
in various types of anemias, lymphomas, leukemia
and other disease states:
 Hemorrhage
 Chronic inflammatory diseases
 Organ failure
 Overhydration
 Pregnancy (normal dilutional effect)
 Subacute endocarditis
 Hemoglobinopathy
 Hemolytic anemia
 After puberty, females have lower RBCs and Hgb due to menstrual
bleeding!
28

RBC indices
• RBC indices (also known as Wintrobe indices) are
useful in the classification of anemias.
• These indices include:
 the Mean Corpuscular Volume or Mean Cell
Volume(MCV)
 The mean cell hemoglobin (MCH), and
 the Mean corpuscular Hemoglobin
Concentration(MCHC)
30

MCV
• Normal Range: 76 – 100 fL
• MCV provides an estimate of the average volume
of erythrocyte.
• The higher the average size, the larger the
average size of the RBC
• Cells with abnormally large MCV are classified as
macrocytic
• Cells with a low MCV are referred to as
microcytic
32

Cont’d
• Cells that have an MCV that falls within the normal range are referred to as
normocytic.
• Increased MCV…..Macrocytic Anemia!
– Associated with folate deficiency, vitamin B12 deficiency, alcoholism, chronic liver
disease, hypothyroidism, anorexia nervosa
– Valproic acid, zidovudine, stavudine
• Decreased MCV….Microcytic Anemia!
– Iron deficiency anemia, hemolytic anemia and lead poisioning
• The MCV can be normal in a patient with a “mixed” (microcytic and
macrocytic) anemia.
• Note that a direct assessment of a blood smear via microscopic
examination is the gold standard for confirming RBC size. 33

Mean Corpuscular Hemoglobin
• Normal range: 26 – 34 pg/cell
• Indicates the average weight of hemoglobin in the
RBC.
• Cells with a low MCH are pale in color and are referred to
as hypochromic.
• Cells with an increased MCH are hyperchromic.
• Cells with normal amounts of hemoglobin are
normochromic.
34

Cont’d
• Increased MCH
– Folate or vitamin B12 deficiency
– In hyperlipidemia patients, MCH may be
falsely elevated because of specimen
turbidity.
• Decreased MCH
– Associated with iron deficiency anemia
35

Mean corpuscular Hemoglobin
Concentration
• Normal Range: 32 – 37 g/dl
• MCHC is a measure of average hemoglobin
concentration in the RBC.
• Increased MCHC
– Associated with hereditary spherocytosis
• Decreased MCHC
– Iron deficiency anemia, hemolytic anemia, lead
poisioning
36

Reticulocytes
• Normal Range: 0.1 – 2.5 % RBC
• Reticulocytes are immature RBCs formed in the
bone marrow.
• An increase in reticulocytes usually indicates
– an increase in RBC production
– decrease in the circulating number of mature
erythrocytes.
• Increased (reticulocytosis)
– Hemolytic anemia, hemorrhage 37

Cont’d
• Decreased
– Infectious causes, alcoholism, renal disease
(from decreased erythropoietin), drug induced
bone marrow suppression
38

REFERENCE RANGE: 4–11 × 103/ΜL OR 4–11 × 109/L
White Blood Cell or Leukocyte Count
39

WBC
40
• It comprise five different types of cells.
• Neutrophils are the most abundant of the circulating WBCs, followed in order
of frequency by lymphocytes, monocytes,eosinophils, and basophils.
• The neutrophils, eosinophils, basophils, and monocytes are formed from
stem cells in the bone marrow.
• Lymphocytes are formed primarily in the lymph nodes,thymus, spleen, and,
to a lesser extent, bone marrow.
• Each WBC type has unique functions, and it is best to consider them
independently rather than collectively as “leukocytes.”
• Ultimately, all WBCs contribute to host defense mechanisms.
• A convenient mnemonic for remembering the various types of WBCs is
“Never Let Monkeys Eat

WBC
• WBC count represents the total number of WBCs in a given
volume of blood.
• Mature WBCs exist as
– Neutrophils
– Lymphocytes
– Monocytes
– Eosinophils
– Basophils
• WBC count with differential provides a breakdown of the
percentage of each.
41

Cont’d
• Increased (leukocytosis)
– Infection, leukemia, trauma
• Decreased WBCs (leukopenia)
– Viral infection, aplastic anemia, bone marrow
suppression caused by cancer chemotherapy
42

Neutrophils
• Normal range:
– Seg 36 – 73 %
– Bands 3 – 5 %
• The terms, polys, segs, polymorphonuclear neutrophils, and granulocytes
are synonymous with the term neutrophil in clinical practice.
• Primary function is to fight bacterial and fungal infections by phagocytosis
of foreign particles.
• An increase in bands, left shift, may occur during infection or leukemia.
 While the bone marrow increases production of new leukocytes,
there is also an increase in the number of circulating immature
neutrophils (e.g., bands); this phenomenon is commonly referred to
as a “left shift,” which suggests bacterial infection
43

Note:
• As the infection progresses, the percentage of band cells may
decrease as a result of an increase in the number of neutrophils
that have a longer half-life.
 This decrease in bands does not necessarily indicate
improvement.
• A decrease in the percentage of neutrophils with a decrease in
the total WBC count is characteristic of effective antibiotic
therapy.
44

AGRANULOCYTOSIS AND ABSOLUTE NEUTROPHIL COUNT
• The condition involving decreased neutrophils, or neutropenia, is defined as a
neutrophil count <2,000 cells/μL;
• agranulocytosis refers to severe neutropenia.
• The degree of neutropenia is often expressed by the absolute neutrophil count
(ANC).
• The ANC is defined as the total number of granulocytes (polymorphonuclear
leukocytes and band forms) present in the circulating pool of WBCs and can be
calculated as WBC × (% neutrophils + % bands)/100.
• Generally, the risk of infection is low when the ANC exceeds 1,000/μL; however,
the risk of infection increases significantlywhen the ANCis less than 500/μL.
• The risk of developing bacteremia is increased further as the ANC decreases to
less than 100/μL, a condition commonly referred to as “profound neutropenia”
 The most commoncauses of neutropenia are metastatic carcinoma, lymphoma, and
chemotherapeutic agents. 45

Cont’d
• Increased Neutrophils (neutrophilia)
– Infection, DKA, response to stress
• Decreased Neutrophils (neutropenia)
– Viral infection, chemotherpy
46

Pools of Neutrophils
1. Bone marrow: many banded forms are
present; neutrophilia with lots of bands
suggest bone marrow was source
2. Circulating Pool: used to deal with day to
day invasion of the body by organisms
3. Marginated Pool: no bands; respond to
physiologic stimulation
47

Case
R.L., a 45-year-old man, is hospitalized with a sustained high fever of 39.4◦C, SOB,
and pleurisy. His cough is productive of rusty sputum, and he appears to be in
acute distress. The results of the CBC and leukocyte differential are as follows:
 Total WBC count, 18,000/μL
• Neutrophils, 76%
• Bands, 13%
• Lymphocytes, 10%
• Monocytes, 0
• Eosinophils, 1%
• Basophils, 0
• On the basis of this laboratory report and other findings, a diagnosis of
pneumococcal pneumonia is suspected. How is R.L.’s laboratory report
consistent with bacterial infection?
48

Lymphocytes
• Normal Range: 20 – 40 %
• Important for immune response to foreign
antigens.
• Increased lymphocytes (lymphocytosis)
– Viral infections and some bacterial infections (e.g.
syphilis)
• Decreased lymphocytes (lymphopenia)
– Acute infections, burns, HIV 49

Monocytes
• Normal range: 2 – 8%
• Synthesized in the bone marrow, released
into the circulation and migrate into
– Lymph nodes, spleen, liver, lung and bone
marrow
– Serve as scavengers for foreign substances
• Increased Monocytes
– Recovery phase of some infections, subacute
bacterial endocarditis, tuberculosis 50

Cont’d
• Decreased Monocytes
– Bone marrow suppressive agent
51

Eosinophils
• Normal Range: 0 – 4%
• Phagocytic white blood cells, assist in the killing of
bacteria and yeast.
• Reside predominantly in the intestinal mucosa and
lungs.
• Involved in allergic reactions and in immune response
to parasites.
• Eosinophil count must be taken at the same time daily
due to diurnal variation.
52

Cont’d
• Increased
– Allergic disorders, allergic drug reactions,
parasitic infections
• Decreased
– Increased adrenal steroid production
53

Basophils
• Normal range: < 1%
• Contain heparin, histamin, and
leukotrienes
– Possibly associated with hypersensitivity
reactions
• Increased
– Hypersensitivity reactions to food or
54

Platelets
• Normal Range: 150,000 – 450,000/ micro
liter
• Critical element in blood clot formation
• Increased platelets
– Infection, malignancies
• Decrease platelets
– Radiation, chemotherapy
55

56
• Platelets are a critical element in blood clot formation.
Reference interval: 150,000-450,000/μL
(SI 150-450 × 109/L)
• The risk of bleeding is low unless platelets fall below 20,000 to 50,000/μL.
Interpretation
• Increased Platelets
– (Thrombocytosis, Thrombocythemia) may be caused by infection,
malignancies, splenectomy, chronic inflammatory disorders (eg,
rheumatoid arthritis), polycythemia vera, hemorrhage, iron deficiency
anemia, or myeloid metaplasia.
• Decreased Platelets
– Thrombocytopenia may occur in autoimmune disorders such as
idiopathic thrombocytopenic purpura (ITP) and also with aplastic anemia,
radiation, chemotherapy, space-occupying lesion in the bone marrow,
bacterial or viral infections, and use of heparin or valproic acid.

Erythrocyte Sedimentation Rate(ESR)
57
Normal Range
Male: 1-15 mm/h (varies with age)
Female: 1-20 mm/h (varies with age)
• The erythrocyte sedimentation rate (ESR) measures the rate of erythrocyte settlement in
anticoagulated blood.
• In the presence of proteins known as acute phase reactants, erythrocytes settle much more
quickly.
• Acute phase reactants are often associated with infectious or inflammatory disorders.
• Thus, the ESR is a nonspecific diagnostic test that may be used to support a diagnosis or
monitor the progress of an inflammatory or infectious process.
• Interpretation:
• The ESR is most valuable in the diagnosis and monitoring of polymyalgia rheumatica and
temporal arteritis.
• The ESR may also be elevated in bacterial infections such as tuberculosis and syphilis,
malignancies, rheumatoid arthritis, SLE, scleroderma, and other collagen vascular diseases.

Interpreting the CBC
• If the neutrophils are causing the leukocytosis,
compare the neutrophil % to total WBC.
• The % neutrophils indicates the severity of
the infection
• The total WBC reflects the quality of the
immune system
58

Interpreting the CBC - Case
5 yr old male with pneumonia
WBC = 18,000
Neutrophils = 60% (10,800)
N.B: Marked leukocytosis and normal range
for neutrophils indicates moderate infection
but excellent immune system response
Excellent prognosis!!!
59

Case
85 yr old female with pneumonia:
Total WBC is: 11,500
Neutrophil % = 80% (9200) bands =
5%
This indicates that a severe infection is
present but the immune system is unable to
respond appropriately.
Prognosis poor!!! 60

Case
20 yr old male admitted following MVA
WBC 14,500
75% neutrophils 1% bands
History and low percent of bands suggest
pseudoneutrophilia
Due to liberation of marginated neutrophils
in the intravascular system
61

QUIZ!
• A.B., a 35-year-old woman, was treated for
7 days with dicloxacillin for cellulitis of the left leg.
On the eighth day, an allergic urticarial rash
developed.
• The CBC showed a total leukocyte count of
10,000/μL with 6% eosinophils.
• What is the significance of this eosinophil
count?
63

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