Automation in the Clinical Lab

Automation in the Clinical Laboratory
Course: Clinical Laboratory Principle (SIMS-443)
ZA School of Medical Technology
1
Dr. Ali Raza
Senior Lecturer
SIMS-SIUT

Automation in the clinical laboratory
 Introduction
Automation of the Analytical Process
Unit Operations
Specimen identification
Specimen preparation
Specimen delivery
Specimen loading and aspiration
Specimen processing
Sample induction and internal transport
Reagent handling and storage
Chemical reaction phase
Measurement approaches
Signal processing, data handling and process control
Applications
2

3

Automation
in the clinical laboratory
Definition:
“ The process whereby an analytical instrument performs
many tests with only minimal involvement of an analyst”
“ Controlled operation of an apparatus, process, or system
by mechanical or electronic devices without human
intervention”
4

Intelligent automation :
• Built in systems to self-monitor and respond
appropriately to changing conditions.
• Instrument performs a repetitive task by itself,
• Instrument performs a variety of different tasks.
5

Advantages of automation
Automated instruments enables laboratories to
 Process much larger workloads
 Reduce number of staff
 Reduction in the variability of results and errors of
analysis
 Significant improvement in the quality of lab tests
 Cost reduction
6

Advantages of Automation
• Assist the laboratory technologist in test performance
(1) Processing and transport of specimens
(2) Loading of specimens into automated analyzers
(3) Assessment of the results of the performed tests.
7

Principle: Automation in the clinical laboratory
 Automated analyzers generally incorporates mechanized
version of basic manual laboratory techniques and
procedures
 Modern instrumentation is packaged in a wide variety of
configurations.
 Common configuration is the Random-Access Analyzer.
8

Random-Access Analysis
Analyses are performed on a collection of specimens sequentially,
with each specimen analyzed for a different selection of tests.
 This approach permits measurement of a variable number and
variety of analytes in each specimen
9

Random-access analysis
 Profiles or groups of tests are defined for a specimen at
the time the tests to be performed are entered into the
analyzer
(1) A keyboard
(2) by instruction from a laboratory information system
(3) Conjunction with bar coding on the specimen tube
(4) by operator selection of appropriate reagent packs
10

Unit Operations
(11) Steps required to complete an analysis are referred to
collectively as unit operations
11

1-Specimen Identification
• The identifying link (identifier) between Patient and
specimen is made at the patient's bedside
• Maintenance of identifier should remains throughout
(1) Transport of the specimen to the laboratory,
(2) Specimen Analysis,
3) Preparation of a Report
12

1- Specimen Identification
Automatic Identification and Data Collection (AIDC)
 Electronically detect a unique characteristic or unique data
string associated with a physical object.
Example of identifiers:
(1) Serial number
(2) Part number
(3) Colour
(4) Manufacturer
(5) Patient number
13

Automatic Identification and Data Collection
14

Bar Coding
• Incorporation of bar coding
technology into analytical systems.
• Initiating bar code identification at a
patient's bedside ensures greater
integrity of the specimen's identity in
an analyzer.
16

Labeling
• Electronic entry of a test order for a uniquely
identified patient generates a specimen label bearing
a unique laboratory Accession Number.
 Laboratory station
 Nursing station
• The unique label is fixed to the specimen
collection tube when the blood is drawn.
17

labeling
A- Primary labeling
B-Secondary labeling
18

A- Primary labeling
 Arrival of the Specimen (log-in)
 Patient Identification and Collection Information
 Laboratory Requisition Form
 An Accession Number
19

A- Primary labeling
Proper alignment of the label on the collection tube
20

B-Secondary labeling:
• Bearing essential
information from the
original label must be
affixed to any secondary
tubes created.
• E.g:
Serum removal from the
original tube
21
A number may be handwritten on the specimen cup,
or a coded label may be affixed to the original tube or
to a specimen cup.

Bar Coding System
Composition:
 Bar code Printer
 Bar code Reader/ Scanner.
22
Bar code Reader
Bar code Printer

Bar Coding System
Symbology :
• describe as the rules specifying the way the data are
encoded into the bars and spaces.
 Specification for that symbology.:
• The width of the bars and spaces,
• The number of each bar
Different combinations of the bars and spaces
represent different characters.
23

Bar Coding System
• When a bar code scanner is passed over the bar code, the
light beam from the scanner is absorbed by the dark bars
and not reflected;
• But the beam is reflected by the light spaces.
• A photocell detector in the scanner receives the reflected
light
• converts that light into an electrical signal that then is digitized.
25

Bar Coding System
 One-dimensional bar coding systems
 Two-dimensional bar coding systems
26

One-dimensional bar coding systems
is an array of rectangular bars and spaces arranged in a
predetermined pattern following unambiguous rules to
represent elements of data referred to as characters.
27

Two-dimensional bar coding systems
 The data is encoded based on both the vertical and horizontal
arrangement of the pattern, thus it is read in two dimensions.
 doesn't just encode alphanumeric information.
 use patterns of squares, hexagons, dots, and other shapes to
encode data.
 Example:
 Data Matrix
 QR Code
 PDF417
 or
28
PDF417

Choice for automatic identification: Bar Code Technology
“Decrease in identification Errors”
29

Errors
“The state or condition of being wrong in conduct or
judgement.”
“ A measure of the estimated difference between the
observed or calculated value of a quantity and its true
value.”
30

Errors
• Human misreading of either specimen label or
loading list may cause
• misplacement of specimens, calibrators, or
controls.
31

Identification Errors
 Error risks begin at the bedside
 Compounded with each specimen processing step
between collection and analysis.
• High risks with hand transcription :
• Accessioning,
• labeling and relabeling,
• Creation of load lists.
32

2- Specimen Preparation
• Manually Specimen Preparation process results in a delay
• Examples :
 Clotting of blood
 Centrifugation
 Transfer of serum to secondary tubes
34

2- Specimen Preparation
• Whole blood assay system: specimen preparation time
essentially is eliminated.
• Automated or semi automated ion-selective electrodes:
Measure ion activity in whole blood rather than Ion
concentration
35

3- Specimen Delivery
Methods are used to deliver specimens to the lab
1) Courier Service
2) Pneumatic tube systems
3) Electric track vehicles:
4) Mobile robots
37

Courier Service
 Collection site to the lab and between lab
 At a given pick up point and specified time.
 Arrangement of immediate pick up adds cost to the analytical
process
 Specimen breakage
38

Pneumatic tube systems
 Propel cylindrical containers through networks
 By compressed air or by partial vacuum.
used for transporting solid objects
39

Electric track vehicles
• Conveyor system for light goods transport.
• utilizes independently driven vehicles
• traveling on a monorail track network
40

Mobile Robots
41
Successful to transport lab
specimen both within lab and
outside lab.
Various sizes and shapes of
specimen containers
Programmable
Cost effective

4- Specimen loading and Aspiration
42

4- Specimen Loading and Aspiration
• Automatic analyzer directly analyzed serum/plasma from
primary collection tube
• Serum transferred from the specimen tubes to cups
CUP features:
• Permit required volume for testing
• Made of inert material
• Disposable
• Minimize cost
• Minimize Evaporation
43

• Specimens may undergo
• Evaporation
• Degradation
a) Thermo-labile Analytes: Temperatures
b) Photo labile Analytes : Photo degradation. E.g.: Bilirubin
• Specimens and calibrators are held at refrigerated loading zone
for Thermo-labile Analytes
• Reduced Photo-degradation by
• Semi-opaque cups
• smoke- or orange-colored plastic covers
The loading zone: area in which specimens are held in the instrument before they are
analyzed.
44

 Contamination
• Splatter of serum
• Stoppers of primary containers are opened
• Decant serum into specimen cups
45

 Contamination
 Closed container sampling systems
• Initially penetrates the primary container's rubber stopper,
followed by
• the specimen probe passes through a hollow needle
• Prevents damage or plugging of the specimen probe
• After the specimen probe is withdrawn, the outer hollow
needle also is withdrawn so that the stopper reseals and no
specimen escapes.
• Examples: Automated hematology and chemistry analyzers.
46

5- Specimen Processing
 Automation of analytical procedures requires removal of
• Proteins
• Other interferants
 To automate this separation step, several automated
immunoassay analyzers use bound antibodies or
proteins in a solid phase format.
48

5- Specimen Processing
• Binding of antigens and antibodies occurs on a solid
surface to which the antibodies or reactive proteins
have been adsorbed or chemically bonded.
 Solid phases are
(1) Beads
(2) coated tubes
(3) Microtiter plates
(4) Magnetic & Nonmagnetic Microparticles
(5) Fiber matrices
49

6- Sample introduction and internal transport
50

6- Sample Introduction and Internal Transport
• Sample introduction into the analyzer and its subsequent
transport within the analyzer
A) Continuous-flow Systems
B) Discrete Processing Systems
51

Continuous-flow Systems
A type of sample analysis in which each specimen in a
batch passes through the same continuous stream at the
same rate and is subjected to the same analytical
reactions
52

Discrete Processing Systems
A type of analysis in which each specimen in a batch has
its own physical and chemical space separate from other
specimen.
53

A) Continuous-flow Systems:
• Peristaltic Pump
• Sample is aspirated through the sample probe
• into a stream of flowing liquid, whereby transported to
analytical stations in the instrument
• To ensure proportionality between calibrators, controls, and
specimens, the pump and roller speed must remain constant.
Peristaltic pump
54

B) Discrete Processing Systems
• Positive-liquid-displacement pipettes
• Specimens, calibrators, and controls are delivered
by a single pipette to the next stage in the analytical process.
• A positive-displacement pipette designed for
1- to dispense only aspirated sample into the reaction receptacle
2- to flush out sample together with diluent.
55

6- Sample Introduction and Internal Transport
• Carry-Over:
Transport of a quantity of analytes or reagent from one specimen
reaction into and contaminating a subsequent one.
56

Carry-Over
• Minimized by
• Adequate flush-to-specimen ratio and incorporating wash
stations for the sample probe.
• Wiping the outside of the sample probe to prevent transfer of
a portion of the previous specimen into the next specimen
cup.
• Using New pipette tip for each pipetting
57

7- Reagent handling and storage
58

7- Reagent Handling and Storage
• Reagent Handling:
Labels on reagent containers include information such as
(1) Reagent identification
(2) Volume of the contents or number of tests
(3) Expiration date
(4) Lot number
Storage
• Plastic or glass containers used for reagents storage
59

Automated Analyzers are classified as
 Open-system analyzer
 Closed-system analyzer
60

Open Versus Closed Systems
Open system
• change the parameters
related to an analysis
• prepare "in-house" reagents
• use reagents from a variety
of suppliers.
• Less expansive
• Longer stability
Closed system
• reagent to be in a
unique container or
• format provided by the
manufacturer.
• Expansive
• Shorter stability
61

8- Reagent Delivery
• Liquid reagents are acquired and delivered to mixing
and reaction chambers either by
• Pumps (through tubes)
• Positive-displacement syringe devices
63

9- Chemical Reaction Phase
• Sample and reagents react in the chemical reaction
phase.
• Factors are important in this phase
(1) Vessel in which the reaction occurs
(2) Cuvet in which the reaction is monitored
(3) Timing of the reaction(s)
(4) Mixing and transport of reactants
(5) Thermal conditioning of fluids.
65

9- Chemical Reaction Phase
 Reaction vessels: Reused in many instruments.
• Time before reusable must be replaced depends on their
composition . E.g.:
• 1 month for plastic
• 2 years for standard glass vessels
• Not replaced unless physically damaged. Pyrex glass
 Cuvet: disposable cuvets
• simplified automation
• eliminated carryover and maintenance of flow cells.
• development of improved plastics ( acrylic and polyvinylchloride)
and manufacturing technology.
66

 Timing of the reaction(s):
• The time allowed for a reaction to occur depends on a variety of
factors.
• Reaction time depends on the rate of transport of reaction mixture
through the system to the measurement station.
 Mixing and transport of Reactants
1. Forceful dispensing
2. Magnetic stirring
3. Vigorous lateral displacement
4. A rotating paddle
5. Use of ultrasonic energy
67

 Thermal Regulation:
 Establishment of a controlled temperature environment
in close contact with the reaction container
 Efficient heat transfer from the environment to the
reaction mixture.
68

10- Measurement Approaches
 Photometers
 Spectrophotometer
 Fluorometers
 Luminometers
70

10- Measurement Approaches
(Photomety or Spectrophotomety)
The measurement of absorbance requires the following three basic
components
1. An optical source: Radiant energy sources used in automated
systems
• E.g: Tungsten, quartz-halogen, deuterium, mercury, xenon lamps,
and lasers.
• Spectrum wavelengths 300 to 700 nm.
71

2. Spectral Isolation
• Spectral isolation is achieved by Interference filters.
• Filters have peak transmissions of 30 - 80% and bandwidths
of 5 to 15 nm
• Filters are mounted in a filter wheel,
• Appropriate filter is moved into place under command of the
system's computer
72

Spectral Isolation
• Monochromators with gratings and slits provide a continuous
choice of wavelengths.
• Coupled with a stationary photodiode array, to isolate the
spectrum.
• These two elements also are coupled with fiber-optic light
guides to transfer the passage of light energy through cuvets
at locations convenient for mechanization.
73

3. A detector
• Photometric Detectors:
• Photodiodes used as detectors in many automated
systems
• Provide a high signal to noise ratio and fast detector
response times for fluorescent and chemiluminescent
measurements.
74

3. A detector
• Notes:
• Proper alignment of cuvets with the light path(s) is important
in both automated and manual analyzers.
• Stray energy and internal reflections must be kept to acceptable
levels.
• If the light path is not perpendicular to the cuvet, inaccuracy and
imprecision may occur, particularly in kinetic analyses.
75

Reflectance Photometry
• In reflectance photometry diffuse reflected light is measured.
• The reflected light results from illumination, with diffused
light, of a reaction mixture in a carrier or from the diffusion
of light by a reaction mixture in an illuminated carrier.
• The intensity of the reflected light from the reagent carrier is
compared with that reflected from a reference surface.
77

Fluorometry
• emission of electromagnetic radiation by a species that has
absorbed exciting radiation from an outside source.
• Intensity of emitted (fluorescent) light is directly proportional to
concentration of the excited species
• used widely for automated immunoassay.
• It is approximately 1000 times more sensitive than comparable
absorbance spectrophotometry,
• but background interference due to fluorescence of native
serum is a major problem.
78

Turbidimetry and Nephelometry
• Turbidimetry and nephelometry are optical techniques
• Are applicable to methods measuring the precipitate
formation in antigen-antibody reactions
• These techniques are used to measure plasma proteins
and for therapeutic drug monitoring.
79

Chemiluminescence and Bioluminescence
• Chemiluminescence and bioluminescence differ from fluorometry
in that the excitation event is caused by a chemical or
electrochemical reaction and not by photo-luminescence
• The applications of chemiluminescence and bioluminescence
have increased significantly with the development of automated
instrumentation and several new reagent systems.
• Because of their attamole-to-zeptomole detection limits,
chemiluminescence and bioluminescence reactions have been
used widely as direct and indicator labels in the development of
immunoassays.
80

Electrochemical
• The most widely used electrochemical approach involves ion-
selective electrodes.
• These electrodes have replaced flame photometry in the
determination of sodium and potassium.
• Electrochemical detectors also have been used for the
measurement of other electrolytes and indirect application in the
analysis of several other serum constituents
• The relationship between ion activity and the concentration of
ions in the specimens must be established with calibrating
solutions, and such electrodes need to be recalibrated frequently
to compensate for alterations of electrode response.
81

11- Signal Processing, Data handling and Process
Control
82

11- Signal Processing, Data handling and Process Control
• The interfacing and integration of computers into automated
analyzers and analytical systems has had a major impact on the
acquisition and processing of analytical data.
• Analogue signals are converted to digital forms by analog-to-
digital converters.
• The computer and resident software then process the digital data
into useful and meaningful output.
• Data processing has allowed automation of such procedures as
nonisotopic immunoassays and reflectance spectrometry because
computer algorithms readily transform complex, nonlinear
standard responses into linear calibration curves.
83

Several functions performed by integrated computers in
automated analyzers
• Command and phase the electromechanical operation
of the analyzer are performed
• Uniformly
• Repeatable
• Correct Sequence
• Control of operational features of automated equipment,
• calculation of results,
• monitoring of operation contribute to the increased
reproducibility of results. 84

• Computers acquire, assess, process, and store operational
data from the analyzers.
• Monitor instrument functions for correct execution and react
to improper function by recording the site and nature of the
malfunction.
• Computers enable communication interactions between
the analyzer and operator.
• Diagnostic computer messages to the user describing the site
and type of problem enable quick identification of problems
and prompt correction.
• Graphical displays provide detailed and interactive
troubleshooting guidance to instrument operators and visual
display of the status of each specimen and associated quality
control data. 85

• Permit interactive communication between computer
systems in the modem laboratory analyzer and the
Laboratory Information System (LIS).
• Instrument manufacturers have been developing ethernet
interfaces for networked connections with TCP/IP
(Transmission Control Protocol/lnternet Protocol).
86

Workstation
(1)Serves as the point of interaction with the instrument
operator
(2)Accepts test orders
(3)Monitors the testing process
(4) Assists with analysis of process quality
(5) Provides facilities for review and verification of test results
87

Workstation
The workstation is usually directly interfaced with the LIS
host, accepting downloaded test orders, and uploading
test results.
Most workstations have facilities to
(1) display Levy-Jennings quality control charts,
(2) monitor the progress of each test order, and
(3) troubleshoot the analyze
88

Integrated automation for clinical laboratory
1. Chemistry
2. Hematology
3. Immunoassay
4. Coagulation
5. Microbiology
6. Nucleic acid testing
• Provide efficient and cost-effective operation with a
minimum of operator input.
89

Instrument Cluster
To reduce labor costs, instrument manufacturers are
developing approaches that will allow a single
technologist to simultaneously control and monitor the
functions of several instruments.
90

Automation
Processes have been automated and used in the clinical
laboratory.
1. Urine analyzers
2. Cell counters
3. Nucleic acid analyzers
4. Microtiter plate systems
5. Automated pipetting stations
6. Point of- care testing analyzers.
91

Automation
Urine Analyzers
 Many of the same analytical principles are used for the
quantification of serum and urine constituents.
 It is more difficult to automate testing of urine than serum
because of the broad range of concentrations of many urine
constituents.
 This requires a low limit of detection to measure low
concentrations, and expanded linearity to permit measurements
of high concentrations without dilution.
 This requirement, together with the relatively low demand for
urine tests compared with that for serum tests, has restricted
the development of analyzers designed specifically for urine
constituents. 92

1. Cell Counters:
 Analyzers that perform a complete blood count have been
automated through the use of the "Coulter principle,'' which
is based on
(1) Cell conductivity
(2) light scatter
(3) Flow cytometry.
93

1. Cell Counters
The Coulter principle is based on changes in electrical impedance produced by
nonconductive particles suspended in an electrolyte as they pass through a small
aperture between electrodes.
 In the sensing zone of the aperture, the volume of electrolyte displaced by the particle
(cell) is measured as a change in voltage that is proportional to the volume of the
particle.
By carefully controlling the quantity of electrolyte drawn through the aperture, several
thousand particles per second are counted and sized individually.
Red blood cells, white blood cells, and platelets are identified by their sizes.
Alternating current in the radiofrequency range short-circuits the bipolar lipid layer of
the cell membrane, allowing energy to penetrate the cell.
 Information about intracellular structure, including chemical composition and nuclear
volume, is collected with this technique.
94

Flow Cytometry
 Cells stained with a fluorescent dye that travel in suspension one
by one past a laser light source. (Unstained cells also are
measured.)
 Scattered light and emitted light are collected in front of the light
source and at right angles, respectively.
 Information derived through measurement of light scatter when
a cell is struck by the laser beam is then used to estimate
(1) Cell Shape
(2) Size
(3) Cellular granularity
(4) Nuclear lobularity
(5) Cell surface structure
95

Automation
Nucleic Acid Analyzers:
 Automation of the analysis of nucleic acids developed
rapidly as an outgrowth of the Human Genome Project.“
 Several manufacturers have developed automation to
assist with the isolation of nucleic acids and with
analysis of nucleic acids using several amplification
schemes and nucleic acid sequencing.
 Many of these techniques have been miniaturized using
chip technology Microfluidic chip
96

Microtiter Plate Systems
 Commonly used in immunoassays and nucleic acid analyses.
 As used for enzyme-linked immunosorbent assay (ELISA) assays,
microtiter plates usually are made of polystyrene and have 48 or
96 wells coated with antibody
specific for the antigen of interest.
 After incubation of serum in the microtiter plate well, the well is
washed to remove unbound antigen, and a second antibody with
conjugated indicator
enzyme is added.
97

Microtiter plate systems
 After a second incubation period, the well is washed to remove the unbound
conjugate.
 A color producing product is developed by the addition of enzyme substrate and
the reaction is terminated at a specific time.
 With the development of automated pipetting stations, the liquid handling steps
required for microtiter plate assays have been fully automated to make
microtiter plate assays a viable technology for carrying out large numbers of
immunoassays.
 Automated pipetting stations have a cartesian robot with a pipette fixed to the
end of a probe that moves about a rectangular space.
 The probe is capable of moving in the X, Y, and Z axes. Liquids may be aspirated
and dispensed in any location within the rectangular space.
98

Automatic Pipetting stations
• used to automate an analytical procedure for which an
automated analyzer does not exist or cannot be justified.
Pipetting robots are
(1) Easy to program
(2) Rarely malfunction
(3) delivering aliquots with precision and accuracy.
(4) Multiple-channel pipetting Robots:
allow parallel processing of specimens with 8- or 12-
channel probes to handle microtiter plates.
99

Point-of-Care Testing Analyzers
(POCT Analyzers )
• known by a variety of names
 "near-patient"
 "decentralized"
 "off-site" testing
• Rapidly growing component of laboratory testing
100

101
Reference:
Tietz Fundamentals of Clinical Chemistry,
Sixth Edition. Automation in the clinical laboratory,
Chapter 11, pg. 171-187

Automation in the Clinical Lab

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