Quality assurance in medical laboratory

Quality Control and Quality Assurance Dr/Faiz Al-Khawlani
For medical labs students1
Introduction to Quality Assurance and Quality Control
Quality assurance (QA) is the overall program that ensures that the results
reported by the testing laboratory are correct. Quality Assurance
Programmes ensure laboratory staff, clinicians and patients that
laboratory test results are reliable, reproducible and relevant. A National
Quality Assurance programme that includes Internal Quality Control,
External Quality Assessment and Quality Management is an effective
tool to improve trust in laboratory test results. The course of Quality
assurance (QA) is suitable for both laboratory assistants and laboratory
technicians, with at least three years of practical work experience. As far
as possible, laboratory assistants and technicians should be grouped in
different training courses to maintain an equal level of background
knowledge. Laboratory personnel who have worked only in vertical
disease-specific programmes should not be included, unless they have
received two months refresher training. The ultimate goal of any quality
system is to obtain test results that are reliable, relevant and
reproducible.
Quality Assurance
 It is an ongoing, comprehensive program, which analyzes every
aspect of an entire operation; it involves determining a quality goal,
deciding whether the goal has been achieved, and implementing
corrective action if the goal has not been reached.
 In the laboratory, quality assurance involves the entire testing
process: pre-analytical, analytical (testing), and post-analytical
processes.

The QA program must:
 Assess the effectiveness of the lab’s policies and procedures.
 Identify and correct problems.
 Assure the accurate, reliable, and prompt reporting of test results.
 Assure the adequacy and competency of the staff.
Standards for Quality Assurance
The first standard emphasizes having a system in place for monitoring
and evaluating the procedures for Patient Test Management, including:
 Patient preparation
 Specimen collection
 Labeling
 Preservation and transportation
 Test requisition completeness
 Relevance and necessity for testing
 Use of appropriate criteria for specimen rejection
 Test report completeness
 Relevance and accuracy
 Timely reporting of results
 Accuracy and reliability of test reporting systems
 Storage and retrieval of result
Quality Assurance Programme
The QA program consists of the following components:
1. Internal Quality Control (IQC)
2. External Quality Assessment (EQA)
3. Quality Management

Internal Quality Control
QC refers to the measures, which must be included during each assay to
verify that the test is working as it should.
Internal Quality Control (IQC)
 Done during daily routine work
 Provides an immediate control
 Errors are corrected immediately
Aims of Internal Quality Control (IQC)
 Ensure that test results are reliable
 Ensure that test results are reproducible
 Quality Control of daily routine work
External Quality Assessment (EQA)
EQA is defined as a system for comparison the laboratory’s performance
using an external agency or facility.
Aims of External Quality Assessment
 Evaluates past performance
 To detect hidden problems
 To compare our performance with others
 To confer more confidence for the lab staff
Types of External Quality Assessment EQA
Several EQA methods or processes are commonly used. These include:
 Proficiency testing
 Rechecking or retesting
 On-site evaluation
Proficiency testing ‫اﺧﺘﺒﺎر‬‫اﻟﻤﮭﺎرة‬ ‫أو‬ ‫اﻟﺨﺒﺮة‬
 Proficiency testing is the most commonly employed type of EQA, as

it is able to address many laboratory methods.
 Proficiency testing is available for most of the commonly performed
laboratory tests, and covers a range of chemistry, haematology,
microbiology, and immunology testing.
 Proficiency testing schemes (PTS) are inter-laboratory comparisons
(‫اﻟﻤﺨﺘﺒﺮات‬ ‫ﺑﯿﻦ‬ ‫)ﻣﻘﺎرﻧﺔ‬ that are organized regularly to assess the
performance of analytical laboratories and the competence of the
analytical personnel”.
 A program in which multiple samples are periodically sent to
members of a group of laboratories for analysis and/or identification;
whereby each laboratory’s results are compared with those of other
laboratories in the group and/or with an assigned value, and reported
to the participating laboratories and others”.
Proficiency Testing Process
In the proficiency testing process:
1. The laboratories receive samples from a proficiency-testing provider.
This provider may be:
 An organization,
 Central reference laboratories, and
 Manufacturers of kits or instruments
2. Samples are provided at regular intervals (3-4) times yearly.
3. Samples must be processed by normal testing method(s) and involve
personnel who routinely perform the testing.
4. The laboratories participating in the program analyze the samples and
return their results to the central organization (provider).
5. Results are evaluated and analyzed, and the laboratories are provided

with information about their performance and how they compared
with other participants.
6. The participating laboratories use the information regarding their
performance to make appropriate changes and improvements.
Retesting
 It is often performed outside a traditional laboratory, and by persons
who are not well trained in laboratory medicine.
 Retesting method is used for HIV rapid testing and may other rapid
tests.
 Retesting of some of the samples using a different more developed
such as enzyme immunoassay (EIA) or ELISA (enzyme-linked
immunosorbent assay) helps to assess the quality of the original
testing.
Characteristics of Retesting
 Done by a reference laboratory, to ensure quality.
 Performed on serum collected at the time of the rapid test
performance and not performed as a blinded process.
Rechecking
 This method is most commonly used for acid-fast smears or Malaria
slides; the slides that have been read in the original laboratory are
“rechecked” in a reference laboratory (that is outside the original
laboratory).
 This allows for the accuracy of the original report to be evaluated, and
allows for the assessment of the quality of the slide preparation and
staining.

Principles of Rechecking Method
The following principles are important when performing recheck
procedures.
 The slides for re-examination must be collected randomly.
 Rechecking must be based upon statistical considerations.
 A common method is for the central laboratory to recheck 10% of
negative and 100% of positive slides.
 It is recommended that rechecking be done in a blinded fashion, so
that the laboratorian performing the retest does not know the original
results.
On-Site Evaluation
 On-site evaluation is a periodic visit by evaluators for on-site
laboratory assessment that is a type of EQA that has been used when
other methods of EQA are not feasible or effective. Again, this
method has most frequently been employed for assessment of sites
performing AFB smears, and those performing HIV rapid testing.
 On-site evaluation for the purpose of EQA may be conducted by a
central reference laboratory or other health authorities.
 Can give a true picture of a laboratory’s overall performance, and
offer real time guidance for improvements that are needed;
 Requiring staff time and travel time and expenses of those performing
the evaluation.
 Measure gaps or deficiencies
On-site evaluation can be a valuable tool to:
 Obtaining a realistic picture of laboratory practices by observing the
laboratory under routine conditions in order to check that it is meeting
quality requirements;

Quality Management
 Training of laboratory staff
 The use of SOPs
 Standard supply management
 Standard equipment management
 Supervision and organization
Aims of Quality Management
 Enables us to produce quality results
 Ensure that test results are affordable
 Ensure that test results are relevant
 Ensure that test results are interpreted correctly
 Ensure that quality assurance is continuous
The Three Stages of Quality Assurance
1. Pre-analytical Stage Quality Assurance
2. Analytical Stage Quality Assurance
3. Post-analytical stage Quality Assurance
Pre-analytical Stage Quality Assurance
 Management and organization of the laboratory
 Usefulness of the requested test
 Patient preparation
 Specimen collection
 Specimen storage
 Specimen transportation
Analytical Stage Quality Assurance
 Internal Quality Control procedures
 Standard Operating Procedures
 Reagents and stains
 State of the equipment

Post-analytical stage Quality Assurance
 Reading of results
 Recording of results
 Reporting and interpretation of results
 Speed of reporting
 Delivery of the results to the patient or the physician
Standard Operating Procedures (SOPs)
 SOPs are an important part of the quality assurance programme.
 SOPs are written instruction protocols that include all aspects of
laboratory work practices.
 SOPs help prevent mistakes rather than detecting them.
Features of SOPs
 SOPs are written in accordance with a standard format.
 SOPs are written in simple language, readily understood by
employees.
 SOPs contain sufficient procedural details to enable trained staff to
perform the task without supervision.
 SOPs are written by qualified and experienced laboratory officers.
 SOPs must be followed exactly by all staff.
 SOPs must be given a title, identification number and date.
 SOPs are reviewed and updated on a regular basis.
Quality control samples
 In order to assure that a test run is valid and results are reliable,
Quality Control Samples should be used in the performance of each
assay.

 The Quality Control Samples should be treated in the exact same
manner as the test samples and are used to validate the test run.
 Each laboratory should develop a criteria for run acceptance based on
guidance from the manufacturer's kit insert and in-lab validation of an
external QC sample.
 Kit Controls –the negative and positive control provided with the kit.
 Quality Control Sample –a low positive externally produced sample.
Use of Statistics in Q.C
 When a diagnostic test is performed in the medical laboratory, the
outcome of the test is a result.
 The result may be quantitative (a number) or qualitative (positive or
negative) or semi-quantitative (limited to a few different values).
 Once the test system is validated, patient results can then be used for
diagnosis or treatment planning.
 For example, when a patient’s serum is tested for potassium, the test
result tells us how much potassium (concentration) is present in the
blood. This result is then used by the physician to determine A quality
control product is a patient-like material ideally made from human
serum, urine or spinal fluid.
 A control product can be a liquid or freeze-dried (lyophilized)
material and is composed of one or more constituents (analytes) of
known concentration.
 Control products should be tested in the same manner as patient
samples.
 A quality control product usually contains many different analytes.
 For example, a general chemistry control can contain any number of
chemistry analytes including potassium, glucose, albumin and
calcium.

 A normal control product contains normal levels for the analyte being
tested.
 An abnormal control product contains the analyte at a concentration
above or below the normal range for the analyte.
 For example, the normal range for a potassium level is about 3.5 – 5.0
mmol/L therefore, a normal control would contain potassium at a
level within this range.
 An abnormal control would contain potassium at a level below 3.5
mmol/L or above 5.0 mmol/L.
 Whether the patient has low, normal or high potassium, Let’s assume
the measured value of potassium in a patient’s serum is 2.8 mmol/L.
 This result is abnormally low and indicates an inappropriate loss of
potassium.
 However, how does the person performing the test know that this
result is truly reliable? It could be possible that the instrument is out
of calibration and the patient’s true potassium value is 4.2 mmol/L –
a normal result.
 The question of reliability for most testing can be resolved by regular
use of quality control materials and statistical process control.
Types of laboratory errors and mistakes
Errors
Non-conforming results with “statistical meaning”. This category
includes all the “wrong” laboratory measures due to non-human action.
Mistakes
Non-conforming results with “no statistical meaning”. This category
contains all the human errors e.g. mixing up samples.

Another classification of errors and mistakes is based on the time and the
stage they appeared in laboratory practice.
1. The pre-analytical errors that involve all the errors, which are
take place before the analysis of the patients’ samples.
2. The analytical errors that include all the errors, which are take
place during the analytical process of the patient’s samples.
3. The post-analytical errors refer to reading and transmission of the
patient’s results from analyzers to the results record, validation of
results that have been produced and posting of the results to
physicians or patients.
According to the previous classification, errors and mistakes are
divided in three corresponding categories:
I) Pre-analytical errors
II) Analytical errors
III) Post-analytical errors
The majority of pre-analytical and post-analytical outliers are
“mistakes” in contrary to analytical outliers that are considered as
“errors”.
Common Pre-Analytical Errors
1. Inappropriate specimen (e.g. wrong specimen-anticoagulant ratio)
2. Wrong anticoagulant (e.g. sodium citrate in place of EDTA)
3. Improper conservation method
4. Inappropriate patient’s preparation (e.g. wrong diet)
5. Mistakes in patients’ identification

Common Analytical Errors
1. Expired reagents which may lead to erroneous results.
2. Expired controls or calibrators.
3. Incorrect pipetting of patient’s sample or reagents.
4. Changes in analyzer’s photometric unit / flow cell / measuring unit
5. Analytical errors influence the repeatability, reproducibility, precision
and accuracy of the analytical methods.
Common Post-Analytical Errors
1. Wrong matching between sample and laboratory’s files,
2. Wrong copy of results from the analyzer’s report to the laboratory
report (in cases of manual transfer),
3. Delay in delivering the results to the physicians, clinics or patients.
4. Loss of the results,
5. Incorrect result reporting or writing,
Basic terms and definitions
Repeatability
Repeatability is the degree of consensus between successive
measurements that have been done on the same sample with very similar
conditions (same analyzer, same user, same laboratory, same methods,
and same lot of reagents) in a very short time.
Reproducibility
Reproducibility is the degree of consensus between successive
measurements achieved on the same sample with different conditions
(e.g. different analyzer, different user, and different lot of reagents) in a
long time.

Accuracy
 Accuracy is the Closeness of the agreement between the result of a
measurement and a true value of the measured. Or
 Describes how a given test result is close to the provided true value.
 Usually expressed in the same units as the result.
 The closeness of measurements to the true value is indicative of the
“accuracy "of the assay.
 Reference samples with known values are needed to check accuracy.
Example:
A hemoglobin reference standard has a known value of 15.0 g/dl. When
tested in two procedures, the following values are obtained for the
hemoglobin concentration:
Procedure A 14.2 g/dl
Procedure B 15.5 g/dl
Which procedure is the most ACCURATE, given this data?
Answer: Procedure A shows a difference of 0.8 g/dl from the actual
value. Procedure B shows a difference of 0.5 g/dl. Therefore, Procedure
B is slightly more accurate than Procedure A.
Precision
Precision is the Closeness of agreement between the measured values
obtained by replicate measurements of an analyte under specified
conditions. or

Describes how a test results are close to one another or to the calculated
mean (x) when repeated analysis of the same material is performed.
Example:
Repeated measurements for the Red Cell Count on a patient sample were
as follows for two automated methods: [all results reported as x 1012
/L]
Instrument #1 4.1
4.1
4.4
4.3
4.2
Instrument #2 5.4
6.2
4.2
5.3
6.2
which machine appears to be most precise? Most accurate?
Answer: Instrument #1 is the most precise, since there is less
interspecimen variability. We don't know which machine is most
accurate, since we don't know what the true hemoglobin value should
have been.
Specificity
Specificity is the certainty that the substance measured by a particular
method is that substance only, and no other.
Sensitivity
Sensitivity refers to the ability of a test to detect the smallest amount of
the analyzed substance that significantly differs from zero.
Reliability
Reliability is the extent to which a given test procedure satisfies the

important criteria of accuracy, precision, specificity, and sensitivity.
Comparison
Comparison of an instrument measurement or reading to a known
physical constant.
Example:
From a PH meter procedure manual:
 Immerse the pH electrode in the reference buffer solution (pH= 7.0).
 Read pH from if the reading 7.0 or close to 7.0, the pH meter work
correctly.
 Immerse the pH electrode in the required solution of unknown pH.
 The resulted reading will be accepted based on the pH of the
reference buffer solution.
Established Laboratory Policies
Laboratory policies should be documented in a reference manual
available to all hospital personnel. This manual should contain
information regarding patient preparation for laboratory tests, and
procedures for reporting abnormal values.
Laboratory Procedure Manual
Should detail each procedure performed in the hematology laboratory,
which indicate that at a minimum the manual, must include:

 Name of the Test Method
 Principle of the Test
 Clinical Application of the Test
 Protocol for Specimen Collection and Storage
 Quality Control Requirements
 Names of Special Chemical Reagents, Equipment or Supplies
 Procedural Protocol
 Normal Values
 Sources of Error
Preventive Maintenance of Equipment ‫ﻟﻠﻤﻌﺪات‬ ‫اﻟﻮﻗﺎﺋﯿﺔ‬ ‫اﻟﺼﯿﺎﻧﺔ‬
Continual monitoring of refrigerator and water bath temperatures,
cleaning and checks of equipment such as microscopes,
spectrophotometers, etc., and adherence to a written preventive
maintenance schedule for all automated equipment is required.
Established Quality Assurance Techniques
 Each procedure should have an established written protocol for
assurance of accuracy of results.
 Limits of acceptable performance must be defined and maintained for
each test performed.
 If control results are not within acceptable limits, the source of the
error must be identified, and the tests repeated before a patient result
may be reported.
 Laboratories should participate in an external program of proficiency
testing, where samples are received in the laboratory from an

external source, and are processed and the results verified by the
proficiency-testing agency.
Accuracy in Reporting Results
 Laboratories should determine "panic values", or critical values or
values significantly different from normal results, or they may track
significant changes from prior patient results "Delta-check".
 Therefore, it is necessary that rechecking again the critical results and
reporting them to the attending physician.
 Results should be reported in writing, and even if STAT results are
communicated by telephone, these results should be followed by a
written report.
Control products (serum, blood, CSF)
 Control is a specimen, which is similar in composition to human
blood or serum/plasma.
 It is treated exactly as patient specimen, and is tested in the same time
with patient specimens.
 The values of the control specimen are known, and may represent
either normal or abnormal values.
 The values of the control specimen may be lower than normal, normal
or higher than normal.

Standard products
 Standard is a highly purified substance of known composition.
 Differs from a control in its composition and in the way it is handled
in the test.
 Standard is used to establish reference points in the construction of
graphs, or to calculate a test result.
Example:
A patient Prothrombin Time is 32 seconds. The normal control time was 12
seconds. The acceptable ranges for the normal control were 11.5-12.5
seconds.
 May the result be reported?
 Is the patient abnormal?
Answer:
YES, to both questions. The control time fell within the range specified, and
therefore the procedure and reagents appear to be functioning correctly.
The patient's clotting time appears to be higher than the normal range.
Example:
From a manual hemoglobin procedure:
"Use the absorbance reading from a digital spectrophotometer, or
convert %T to absorbance, and plot absorbance vs. concentration of
the standard dilutions on linear graph paper. Patient or control results
may then be read from the standard curve."

Quality Assurance in Medical Microbiology
Internal quality assessment (IQA)
 Each laboratory should have an internal quality assessment scheme.
 This can be carried out by regular use of certified reference material,
replicate testing, retesting of retained items and correlation of results
of different characteristics of an item.
Quality Assurance
 When comprehensive control measures and relevant assessments are
in place, a laboratory can claim a level of assurance.
 QA can be seen as the sum of QC, IQA and EQA, i.e., QA = QC +
IQA + EQA.
Pre-Analytical Stage Quality Assurance
 SOPs need to describe selection and appropriate use of
microbiological investigations, proper filling of request form,
collection and transport of specimens, and checks must be made when
the specimen and request form reach the laboratory.
 Each of these can have a minor effect on accuracy of the result.
Appropriate Use of Microbiological Investigations
 This aspect of QA requires collaboration between laboratory
personnel and clinicians.
 Clear guidelines should be provided on the use and value of specific
microbiological investigations.

Request form
A request form must accompany each specimen, which details:
a) Patient’s name, age, gender, occupation, outpatient or inpatient
number, ward or health center,
b) Type and source of specimen, date and time of collection,
c) The required investigation(s),
d) Clinical note summarizing the patient’s illness, suspected diagnosis
and information on any antimicrobial treatment that may have been
started at home or in the hospital,
e) Name of medical officer requesting the investigation,
Collection and Transport of Specimens
 Specimens such as urine and sputum are best collected soon after a
patient wakes up when organisms have had the opportunity to
multiply over several hours.
 Blood for culture is usually best collected when a patient’s
temperature begins to rise.
 The time of collection of most other specimens will depend on the
condition of the patient, and the times agreed between the medical,
nursing, and laboratory staff for delivery of specimens to the
laboratory.
 Every effort must be made to collect specimens for microbiological
investigation before antimicrobial treatment.
 The laboratory must state written instructions to all those
responsible for collecting microbiological specimens.

 It must be kept in mind that the quality of microbiological report is
fundamentally dependent upon:
 The quality of the specimen submitted,
 Nature and timing of specimen
 The suitability of sampling method
 Transport of specimen
 Use of transport media
 Transit time
 Adequacy of information given to the laboratory
Checking of Specimen and Request Form
 When the specimens reach, the laboratory should checks it to ensure
that correct specimen has been sent and the specimen is the same as
that on the request form.
 Also included should be the comment that the specimen requires
immediate attention, e.g., CSF, urine, swabs not in transport media or
faecal specimen containing blood and mucus, etc.
 Dry faecal swab, saliva instead of sputum, eye swab that has not been
freshly collected, and a leaking specimen, are not acceptable.
Analytical stage Quality Assurance
The following should be incorporated in the microbiological SOPs
covering the analytical stage:
 Detailed procedure for examining different specimens,
 Staining techniques and Q.C of stains,
 Aseptic techniques and safe handling of infectious material,
 Preparation and Q.C of culture media and preservation of stock
strains,
 Inoculation of liquid and solid media,
 Reading and interpretation of cultures,

 Techniques used to identify pathogens,
 Antimicrobial sensitivity testing and Q.C of procedures and antibiotic
discs,
 Cleaning and Q.C of equipment used in microbiology laboratory,
 Immunologic techniques and Q.C of antigen and antibody reagents,
 Safe working practices,
 Disposal of specimens and cultures,
 Cleaning of glassware, plasticware, etc.,
 Sterilization procedures and their control,
Quality Control of stains and reagents
 All stains and reagents must be clearly labelled, dated, and stored
correctly,
 All stains and reagents, should not be used beyond their expiry date or
when they show signs of deterioration, such as, abnormal turbidity
and discoloration.
 Control smears should be stained at regular intervals and whenever a
new stain is prepared.
 Control smear for Ziehl-Neelsen stain should include smears with
few to moderate number of AFB.
 Control smear for Gram stain can be prepared from mixed culture of
staphylococci and Escherichia coli. Smear should not be too thick.
 When a smear is too thick, the decolourization is often incomplete
which can result in Gram-negative organisms being reported as Gram
-positive.
Quality Control of Equipment
 All equipment used for tests, having a significant effect on the
accuracy of result of the test therefore, should be calibrated before

being put into service and on regular intervals thereafter.
 For each item of equipment, there should be clear operating and
cleaning instructions, and service sheets.
 Regular cleaning, servicing and maintenance are essential if the
equipment is to remain in good working order and safe to use.
 Specimen containers should be inspected regularly, especially the
caps of bottles and tubes for missing or worn liners.
Quality control of culture media Sterility
 Sterility control is a fundamental check for any medium.
 The level of control depends upon the type of medium.
 A medium that is prepared, dispensed then autoclaved, will require
only one unit to be incubated overnight as a check of sterility.
 Media consisting of various non-sterile products, i.e., blood, serum,
glucose, antibiotics, any other heat-labile or non-filterable solutions
that may then require aseptic dispensing, would require strict sterility
control up to a level of incubation of the entire batch for 3 days; if
detected contamination exceeds 10%, the whole batch should be
discarded.
Performance
A list of suggested organisms and acceptable results for the culture media
most commonly used in clinical laboratories.

Quality control of antimicrobial susceptibility discs
Antimicrobial sensitivity discs must be tested at weekly intervals with
standard control organisms of known susceptibility.
QC of personnel
 There should be continuing education programme and in-service
training.
 The staff should be encouraged to participate as often as possible in
local, regional and national seminars and workshops.
 Blind unknown samples for laboratory testing should be included in
test runs and source of error, if any, should be pin-pointed and
corrected.
Post-analytical stage Quality Assurance
Reporting and verifying of microbiological test results, interpreting test
reports correctly, taking appropriate action when a result has serious
implications for a patient or public health.
Results Reporting
 The terminology and format used in reporting should be standardized
and agreed between laboratory personnel and clinicians.
 Any preliminary report must be followed by a full written report.
 All reports must be checked for correctness and clarity and signed by
head of the department.

 Report distribution and delivery systems must be efficient and urgent
reports should be telephoned at all the significant stages of the
investigation.
 Appropriate steps must be taken to ensure confidentiality of reports
both in the laboratory and during transfer.
 Those receiving the reports should consult the laboratory when any
part of the report is not clear.
 There must be effective communication between those requesting
tests and laboratory staff.
 Microbiologist should be prepared to give advice on the type of
investigations that might be helpful in the diagnosis and be prepared
to advise on antibiotic treatment.
 A patient’s interest is generally better served by an early report of the
provisional identification of a potential pathogen, and its possible
antibiotic sensitivities, than by a delayed report with a precise and
confirmed identification.
External quality assessment (EQA)
 An EQA scheme should include testing for major pathogens.
 It should not be too complicated, costly, or time consuming.
 Although steps may be taken in a laboratory to ensure test results are
reliable, a system of assessing a laboratory to do this to a satisfactory

standard is recommended i.e. an EQA scheme.
 Participation in EQA schemes should always be regarded as
additional to internal QC because it can assess only past performance
when test results have already been reported and acted on.

SOP TITLE: RAPID HIV SCREENING TEST (DETERMINE
METHOD) SOP No.: SERO 001 / 2005 DATE: July 2005
Clinical significance
This test is used for screening antibodies against HIV infection.
Principles of immunochromatography (Determine
method)
Determine is an immunochromatographic test for the qualitative detection
of antibodies to HIV-1 and HIV-2. The sample is added to the sample
pad. As the sample migrates through the conjugate pad, it reconstitutes
and mixes with the selenium colloid-antigen conjugate. This mixture
continues to migrate through the solid phase to the immobilised
recombinant antigens and synthetic peptides at the patient window site.
 If antibodies to HIV-1 and/or HIV-2 are present in the sample, the
antibodies bind to the antigen-selenium colloid and to the antigen at
the patient window, forming a red line at the patient window site.
 If antibodies to HIV-1 and/or HIV-2 are absent, the antigen-selenium
colloid flows past the patient window and no red line is formed at the
patient window site.
Specimen collection and storage
 Serum, plasma, and whole blood collected by venipuncture should be
collected aseptically in such a way as to avoid haemolysis.
 Serum and plasma should be stored at 2–8ºC if the test is to be run
within 7 days of collection. If the testing is delayed more than 7 days,
the specimen should be frozen at -20 ºC .

 Whole blood should be stored at 2–8ºC if the test is to be run within 7
days.
 Whole blood collected by finger stick should be tested immediately.
 Reagents and samples should be at room temperature before testing.
 Requirements Refer to the product literature.
Procedure
Remove the protective foil cover from each test.
For Serum and Plasma
 Apply 50 µL of sample (precision pipette) to the sample pad
(marked by the arrow symbol).
 Wait a minimum of 15 minutes (up to 60 minutes) and read results.
For Whole Blood
 Wait one minute, then apply one drop of chase buffer to the sample
pad.
 Wait a minimum of 15 minutes (up to 60 minutes) and read results.
For Whole Blood (Fingerstick)
 Wait until blood is absorbed into the sample pad, then apply one
drop of chase buffer to the sample pad.
 Wait a minimum of 15 minutes (up to 60 minutes) and read result,

Quality Control
To ensure assay validity, a procedural control bar is incorporated in the
assay device and is seen in the window labelled “control.”
Results
Report as either reactive or non reactive.
Interpretation of Results
• Reactive (positive) (two lines):
Red lines appear in both the control window and the patient window of
the strip. Any visible red color in the patient window should be
interpreted as reactive.
• Nonreactive (negative) (one line):
One red line appears in the control window of the strip and no red line
appears in the patient window of the strip.
• Invalid (no line):
If there is no red line in the control window of the strip (even if a red line
appears in the patient window), the result is invalid and should be
repeated.
Test Limitations and Sources of Error
 The Abbott Determine HIV-1/2 is designed to detect antibodies to
HIV-1 and HIV-2 in human serum, plasma, and whole blood.
 Other body fluids or pooled specimens may not give accurate results.
 Lack of color in the patient bar does not exclude the possibility of
infection with HIV.

A false negative result can occur in the following circumstances:
 Low levels of antibody (e.g., early seroconversion specimens) that are
below the detection limit of the test of Infection with a variant of the
virus that is less detectable by the Determine HIV assay configuration
 HIV antibodies in the patient that do not react with specific antigens
utilized in the assay configuration specimen-handling conditions,
resulting in loss of HIV multivalency Whole blood or plasma
specimens containing anticoagulants other than EDTA may give
incorrect results.
Disposal of waste materials
All materials used in the test must be disinfected preferably in 1% sodium
hypochlorite (Household bleach) before disposal.
Agglutination tests/Rapidtex ASO Latex Test
Intended Use
The RapidTex ASO Latex Test is a rapid latex agglutination test for the
qualitative and semi-quantitative determination of anti-streptolysin-O
antibodies (ASO) in serum. Pre-dilution of patient serum is not required
for qualitative testing.
Summary
In infections caused by β -haemolytic streptococci, streptolysin-O is one
of the two hemolytic exotoxins liberated from the bacteria that stimulates
production of ASO antibodies in the human serum. The presence and the
level of these antibodies in a serum may reflect the nature and severity of
infection.

Principle
The RapidTex ASO latex reagent is a stabilised buffered suspension of
polystyrene latex particles that have been coated with Streptolysin O.
When the latex reagent is mixed with a serum containing ASO,
agglutination occurs. The sensitivity of the latex reagent has been
adjusted to yield agglutination when the level of ASO is greater than 200
IU/ml, a level determined to be indicative of disease by epidemiological
and clinical studies. Sera having titers of between 200 IU/ml and 3500
IU/ml will be reactive.
Reagents and Materials Supplied
ASO Latex:
A stabilized buffered suspension of polystyrene latex particles coated
with Streptolysin O and 0.1% sodium azide as preservative. Shake well
prior to use.
2. ASO Positive Control
Human serum containing more than 200 IU/ml ASO and 0.1% sodium
azide as preservative.
3. ASO Negative Control
Human serum containing 0.1% sodium azide as preservative.
4. Sufficient disposable pipettes
5. Glass test slide
Materials Required But Not Supplied
1. 12 x 75 mm test tubes
2. Timing device
3. Physiological saline
4. Serological pipettes.

Storage & Stability
 When not in use, store reagent and controls at 2 to 8 0
C.
 DO NOT FREEZE.
 Prior to use, allow reagent and controls to warm up to room
temperature.
 Biological indication of product instability is evidenced by
inappropriate reaction of the latex reagent with the corresponding
positive and negative controls.
Precautions
1. This product is For in Vitro Diagnostic Use Only.
2. Even though the control sera supplied in the RapidTex ASO kit have
been tested by an FDA approved method for the presence of Hepatitis
B Surface Antigen and anti-HIV antibodies and found to be non-
reactive, all human serum products and patient specimens should be
considered potentially hazardous and handled in the same manner as
an infectious agent.
3. The preservative sodium azide may react with metal plumbing to form
explosive metal oxides. In disposal, flush with a large volume of
water to prevent metal azide build up.
Specimen Collection and Handling
Only fresh serum specimens should be used. Plasma must not be used
since fibrinogen may cause non-specific agglutination of the latex. It is
preferable to test samples on the same day as collected. Serum samples
may be o stored at 2-8 0
C for up to 48 hours prior to testing. If longer
storage is necessary, sera should be stored frozen

Test Procedure
Method I (Qualitative)
1. Bring all test reagents and samples to room temperature.
2. Use a disposable pipette to draw up and place one free-falling drop of
each undiluted sample into its identified circle of the slide. Retain
each pipette for mixing in step 5.
3. Deliver one free-falling drop of positive and negative control into its
identified circle.
4. Mix the ASO latex reagent by gently shaking. Add one free-falling
drop of reagent to each control and sample.
5. Using the flattened end of the appropriate plastic pipette as a stirrer
(step 2), thoroughly mix each sample with reagent within the full area
of the circle. Discard the disposable pipette.
6. Slowly rock the slide for exactly two (2) minutes and observe for
agglutination under a high intensity light.
7. Record results
8. Re-wash glass slide for future use.
Method II (Semi-quantitative)
1. Set up at least 5 test tubes and label 1:2, 1:4, 1:8, 1:16, 1:32, and etc.
2. Use physiological saline to serially dilute sample to be titered
according to standard laboratory practices.
3. Repeat all steps as in Method I using these new samples.

Results
Qualitative: A test sample is considered to contain ASO antibodies in
excess of 200 IU/ml when agglutination (clumping) is observed when
compared to the result of the negative control.
Semi-Quantitative: The greatest dilution of test sample showing
agglutination is considered as the endpoint.
Multiplication of the factor of dilution by 200 will yield the approximate
level of antibody present. The sensitivity of the RapidTex ASO Test
reagent has been standardized against WHO standard so that positive
reactions will be obtained when samples with titers between 200IU/ml
and 3500IU/ml are assayed. RapidTex ASO Test will not agglutinate in
the presence of samples containing less than 200IU/ml of ASO.
DILUTION
CONCENTRATION (IU/ml)
1:1
1:2
1:4
1:8
1:16
1:32
200
400
800
1600
3200
6400
Quality Control
Perform testing of controls with each series of tests to assure test
conformity and integrity.

Limitations of the Procedure
1. Results obtained must be evaluated together with the clinical
information available to the physician.
2. Serum samples showing gross hemolysis, lipemia, turbidity, or
contamination should not be used since false positive results may
occur. Both elevated Betalipoprotein and cholesterol level may
suppress a rise in ASO titer.
3. The test reaction must be read immediately following the two (2)
minute rocking. Delayed readings may result in false positive results.
4. The degree of agglutination observed in undiluted samples is not
indicative of antibody levels since a prozone effect may limit
agglutination.
5. The RapidTex ASO latex reagent vial must be kept tightly closed to
prevent evaporation and subsequent flocculation.
6. Patient on therapy of penicillin or other antibiotics may suppress a rise
in ASO titer.
7. Only serum specimens should be used. Do not use plasma samples as
they could cause non-specific agglutination of the latex.
Expected Values
A detectable level of 200 IU/ml ASO antibodies is usually regarded as the
normal upper limit since less than 15-20% of healthy individuals
demonstrate titers greater 200IU/ml when their sera are assayed. In most
new borns the titer is initially greater than that of the mother due to
maternally acquired IgG but the new born levels fall sharply during the
first weeks of life.

Normal ASO levels for preschool children are generally less than
100IU/ml but the levels rise with age, peaking in school age and
decreasing in adulthood.
Increases in ASO titer generally occur 1 to 4 weeks after onset of
infection with β -hemolytic streptococci Group A. As the infection
subsides, the titer declines and returns to normal levels within six months.
If the titer does not decrease, a recurrent of chronic infection may exist.
Elevated ASO titers may be associated with ankylosing spondylitis
glomerulonephritis, scarlet fever, and tonsillitis. Increased ASO levels are
generally not found in sera of patients with rheumatoid arthritis except
during acute episodes.
Extremely low levels of ASO have been observed in the blood samples of
patients with nephrotic syndrome and antibody deficiency syndromes.
Performance Characteristics
Total of 354 serum specimens were tested comparing the undiluted with
the direct 1:6 dilution procedure. Equivalent results were obtained on the
qualitative method on 349 of the 354 random specimens. The overall
agreement is approximately 99%.
Measurement by Antibody titer
The highest dilution of serum that gives observable reaction with the
antigen.
Parameters of serological tests
Sensitivity
The ability of the test to detect even minute quantities of antigen or
antibody.

Highly sensitive
Indicate that there is no false negative results.
Specificity
The ability of the test to detect only the specific antigen or antibody.
Highly specific
Indicate that there is no false positive results.

Laboratory Equipment
• All equipment in the laboratory
– Should have instruction manuals regarding proper use and
maintenance requirements
– Should be monitored and recorded for quality control
procedures, function checks, preventative maintenance and
repairs.
– These should be documented and filed in separate log books
• Before putting new equipment or a new method into service – it
must be validated
– This is accomplishment by correlation and/or agreement
studies
– The new method or equipment is validated against old
method and/or equipment
• Refrigerators and freezers
– Record serial numbers
– Record temperatures daily
Maintaining correct temperatures is vital to maintaining the integrity
of reagents and should be maintained as per manufacturers’
instructions.
Pipette’s Impact on Q.C
• Pipette accuracy and precision must checked regularly - the first
time of use and periodically thereafter.

• If either fails, it is important to follow the manufacturer’s
instructions for repair and calibration.
• Improperly calibrated pipettes will affect our assay and should be
checked for precision and accuracy bi-annually.
• Pipettes not passing accuracy checks should be cleaned and
checked for worn parts, and be sent to and serviced by reliable
vendors
• Maintain complete records of pipette calibration function check
• Include serial and other identifying numbers of each pipette
Instrument Maintenance
Required for:
• Producing reliable test results
• Minimizing instrument breakdown
• Lowering repair costs
• Preventing delays in reporting test results
• Maintaining productivity
• Lengthening instrument life
Reagents in Laboratory
How to store reagents
– Always store according to the manufacturer’s
recommendations
– Reagents must be dated and initialed upon receipt.

– Lot numbers must be recorded in a reagent quality control
record book.
– After preparation and/or when placed in service, reagents
must be labeled when put “in service” according to the
manufacturer’s suggested recommendations.
– Reagent parallel testing
– New reagent lots must be checked with old lots using a
normal control before use
– The variability for new lots of reagents compared to the
current lot should not be greater than the variability found
for triplicate samples of the current lot
– Variability should be within 5%
– Results of reagent checks must be recorded, dated and
initialed.
– Document all lot to lot procedures with date and variability
results
PERSONNEL (Staff)
• Restrict all testing procedures to staff with appropriate technical
training
– Testing theory
– Instruments
– Testing procedures
• Perform and document periodic performance assessments on all
testing staff

Documentation
• If you have not documented it, you have NOT done it …
• If you have not documented, it is a RUMOUR !!!
Value of Documentation
• Ensures processes and outcomes are traceable
• Processes can be audited, thus external assessments can take place
• Tool for training
• Reminds what to do next
Key Documents
• Results archive
– File results in an organised and easily accessible manner
• Laboratory monitoring
– Documentation of temperature monitoring, reagent control,
accuracy/precision assays, corrective actions, audit reports
• Instrumentation
– SOPs
– Equipment files + Manuals
– Service history records of the instrument
– Records of daily, weekly and monthly calibrations and
maintenance
Validation
 is about determining whether something does what it is supposed
to do.

Importance of validation
• Validation - before we introduce something
• Re-validation
– after we have changed/modified
– periodic
• Validation is applied to:
– SOP
– reagents
– equipment
– software
Factors influencing quality: Post-analytical
• Right recording and reporting
• Right interpretation
– Range of normal values
• Right turnaround time
• Report to right user
Reporting results
• Proper procedure includes:
– All data entry results should be verified by a section head or
supervisor (when available) and reviewed by management
for final interpretation and release of results
– In the event that a report has already been sent out and needs
correction, a new report is issued with updated report written
on it

• The old report remains in the patient file
– Verbal result reports should be documented, listing the time
of the receipt of the report

Quality Assurance in Biochemistry
Pre-analytical quality assurance
Sample Collection:
The most frequent sample used for biochemistry tests is the venous
blood sample:
 Serum is used for most biochemistry tests carried out at a district
hospital.
 Plasma is the second choice for biochemistry tests if the reagent’s
manufactures recommended that.
 Do not leave the tourniquet on the arm for more than 2 minutes, as
this will affect the concentration of cells and substances in the blood.
 Do not collect the blood from an arm in which an intravenous
infusion is being given.
 Remove the needle from the syringe before pouring the blood into the
collection tube. Transferring the blood through the needle may cause
hemolysis, breaking of the red cells.
 The collection tube must be clean and dry.
 Allow the blood to clot at room temperature away from direct
sunlight.
 Centrifuge the blood and separate the serum as soon as possible, latest
within 1 hour after collection.
 Never store whole blood in the refrigerator, as the cold will cause
hemolysis, breaking of the red cells.
 After centrifugation, remove the serum carefully without sucking up
red cells.
Sample Storage and Transportation:
 After separation of the serum from the blood clot, carry out the

biochemistry test as soon as possible.
 Not all analytes are stable, which means their concentration will
reduce over time.
 Generally, stability is prolonged if the serum is kept in the refrigerator
at 2-8 C0
.
 Some analytes such as bilirubin are also affected by light.
Sampling errors
 There are a number of potential errors, which may contribute to the
success, or failure of the laboratory to provide the correct answers
to the clinician's question. Some of these problems arise when a
clinician first obtains specimens from the patient.
Blood sampling technique
 Difficulty in obtaining a blood specimen may lead to haemolysis
with consequent release of potassium and other red cells
constituents. The results for these will be falsely elevated.
Prolonged stasis during venepuncture
 Plasma water diffuses into the interstitial space and the serum or
plasma sample obtained will be concentrated. Proteins and protein-
bound components of plasma such as calcium or thyroxine will be
falsely elevated.
Insufficient specimen
 Each biochemical analysis requires a certain volume of specimen
to enable the test to be carried out it may prove to the impossible
for the laboratory to measure everything requested on a small
volume specimen.

Errors in timing
 The biggest source of error in the measurement of any analyte in a
24-hour urine specimen is in the collection of an accurately timed
volume of urine.
Incorrect specimen container
 For many analyses, the blood must be collected into a container
with anticoagulant and preservative.
 For example, samples for glucose should be collected into a special
container containing fluoride that inhibits glycolysis; otherwise, the
time taken to deliver the sample to the laboratory can affect the
result. If a sample is collected into the wrong container, it should
never be decanted into another type of tube. For example, blood
which has been exposed even briefly to EDTA (an anticoagulant
used in sample containers for lipids) will have a markedly reduced
calcium concentration, approaching zero.
Inappropriate sampling site
 Blood samples should not be taken 'down-stream' from an
intravenous drip. It is not unheard of for the laboratory to receive a
blood glucose request on a specimen taken from an intravenous
drip. It is not unheard of for the laboratory to receive a blood
glucose request on a specimen taken from the same arm into which
5% glucose is being infused. Usually the results are biochemically
incredible but it is just possible that they may be acted upon, with
disastrous consequences for the patient.

Analytical Quality Assurance
General IQC Procedures:
 Do not examine the specimen, when blood is haemolysed.
 Do not examine the specimen, when the time of the sample collection
is not clear.
 Label the specimen with patient name and lab number to avoid
confusion.
 Take great care when pipetting samples and reagents.
 Care for your colorimeter; cover it with a protective cover when not
in use.
 Handle filters with great care.
 Do not touch the filter with fingers, always hold from the side.
 Prepare standard curves, whenever you use new reagents or
equipment.
 Use commercially available control sera to control accuracy as
possible.
 Do repeated tests or redo test from the day before, to check your
precision.
 Be careful when repeating and redoing tests some analytes are not
stable.
 The serum for blood sugar has to be separated from the blood clot
within one hour after the blood collection and the test should be
done within two hours after collection as the concentration of
glucose decreases over time due to glycolysis.

Bilirubin Total and Direct
Colorimetric Method /End Point
Bilirubin is converted to coloured azobilirubin by diazotized sulfanilic
acid and is measured photometrically. Of the two bilirubin fractions in
serum –bilirubin-glucuronide and free bilirubin which is bound to
albumin– only the former reacts directly, while free albumin reacts after
being displaced from protein by an accelerator. The difference of two
measurements total bilirubin (with accelerator) and direct bilirubin
(without accelerator) enables to calculate indirect bilirubin. The terms
«direct» and «indirect» bilirubin refers exclusively to the reaction
characteristics in the presence or absence of an accelerator or solubilizer
and are only approximate equivalents of the two bilirubin fractions.
Reagents
RT. Sulfanilic acid 29 mmol/L, HCl 0.24 mol/L, Duposol® 3% (w/v).
RD. Sulfanilic acid 29 mmol/L, HCl 0.24 mol/L.
RN. Sodium nitrite 11.6 mmol/L.
Preparation
The Reagents are ready-to-use.
Storage and Stability
 Store at 2-8‫؛‬C.
 The Reagents are stable until the expiry date stated on the label.
 On board the reagents are stable 30 days.
 After daily use stored tightly closed and protected from light.

Discard if appear signs of deterioration:
 Presence of particles and turbidity.
 Blank absorbance (A) at 540 nm > 0.050 in 1cm cuvette.
 Reagent RN if it develops a yellow coloration.
Sample Collection
 Fresh hemolysis-free serum,
 EDTA or heparinized plasma.
 Store in the dark until use.
 Samples can be frozen at –15‫؛‬C or below in which case bilirubin is
stable for 2 months.
Interferences
 Lipemia (intralipid < 5 g/L) does not interfere.
 Direct Bilirubin (Hemoglobin 2 g/L) may affect the results.
 Total Bilirubin (Hemoglobin 16 g/L) does not interfere.
 Other drugs and substances may interfere
 Lipemic samples interfere with the assay.
 The interference can be corrected by preparing a sample blank before
applying the general formula of calculation.
Instrumentation and Materials
 LIDA analyzer.
 Laboratory equipment.
 iso-Clean Solution. Ref. CT18002.
 Multicalibrator CC/H 10x3 mL Ref. CT19750

Automated Procedure
 A graphic display pictures the specific sets corresponding to the
technical application outlined for this test.
 Any new application, to the instrument should be validated to confirm
that results meet the analytical performance of the method.
 It is recommended to validate periodically the instrument.
Calibration
 Recalibrate weekly (Bilirubin T) or every 2 days (Bilirubin D), when
a new lot of reagent is used, when control recovery falls out of the
expected range or when adjustments are made to the instrument.
 Two point calibration is recommended (S1: NaCl 9 g/L and S2:
Calibrator).
 A reagent blank should be run daily before sample analysis.
Results
 Samples with concentrations higher than 20 mg/dL should be diluted
1:2 with saline and assayed again. Multiply results by 2.
 If results are to be expressed as SI units apply: mg/dL x 17.1 =
µmol/L
Expected Values
Adults
 Total Up to 1.0 mg/dL
 Direct Up to 0.2 mg/dL

Newborns (Total Bilirubin)
Full- termPremature
Age
2.0-6.0 mg/dL
1.0-6.0 mg/dL
Up to 24 h
6.0-7.0 mg/dL
6.0-8.0 mg/dL
Up to 48 h
4.0-12.0 mg/dL
10.0-15.0 mg/dL
3-5 days
It is recommended that each laboratory establishes its own reference
range.
Quality Control
 To ensure adequate quality control (QC), each run should include a
set of controls (normal and abnormal) with assayed values handled as
unknowns.
 Each laboratory should establish its own Quality Control scheme and
corrective actions if controls do not meet the acceptable tolerances.
Diagnostic Characteristics
Hyperbilirubinemia (an abnormal elevation of bilirubin, whether
conjugated or unconjugated) in plasma is an indication of a disturbance in
bilirubin metabolism. This condition is caused either by an
overproduction of bilirubin or by an impairment in the metabolic
pathway.
The increase in bilirubin production is usually caused by a rapid
destruction of erythrocytes, resulting from blood diseases such as
hemolytic anemia.

In newborns the increase in bilirubin may be caused by Rh, ABO, or
other blood group incompatibility, by sepsis, hepatic immaturity, or by a
variety of hereditary defects in bilirubin conjugation.
Clinical diagnosis should not be made on findings of a single test result,
but should integrate both clinical and laboratory data.

Quality Assurance Procedures in the Parasitology
Laboratory
1. Equipment
Microscopes:
 Ensure that spare light bulbs are available for all microscopes
 use a camel hair brush to clean eyepieces and all glass surfaces
 use disinfectant (70% isopropyl alcohol) to clean the stage
 Keep microscopes covered when not in use.
 Report any frayed or broken electrical wires.
Centrifuges:
 before each run visually inspect the device for loose or damaged parts
 inspect the interior for signs of leaking on a previous run and clean
with disinfectant as required
 disinfect the centrifuge monthly
 record any problems encountered
Control slides
 Control slides are used in the various staining procedures performed
in the lab.
 Control slides are to be used with each rack of slides to be stained for
the Sequential Stain (routine lab stain).
 The control slides are read by the technologist and the results are
recorded and initialled on record sheets maintained in the Laboratory
Manual.
Participation in Quality Assurance Programs:
 Participation in Quality Assurance Programs which provides stool

samples for preparation, staining and reading.
 All positive malaria bloods are kept and are frozen for PCR testing.
Malaria speciation can then be confirmed by this accepted gold
standard.
 Monthly meetings are held to discuss laboratory related issues and to
determine if an evaluation of a new method is warranted.

Quality Assurance in Hematology
Sample Collection 1: Capillary blood
Haematological tests are carried out with fresh capillary blood or anti-
coagulated venous blood.
 Capillary blood is obtained by directly pricking the finger, the ear-
lobe or the heel of the foot in infants.
 Capillary blood is used immediately and therefore does not need
anticoagulants to be added.
 Capillary blood can be used for Haemoglobin estimation with the
Sahli-Method, Total WBC-Count, Differential WBC-Count, Platelet
count, Reticulocyte count and Blood film for Malaria.
 NEVER use absolute alcohol for disinfecting the skin! Use only 70%
alcohol!
 NEVER use blood that has been squeezed out by force! Rub the
hand and prick another finger again!
Sample Collection 2: Venous blood
 The blood specimen must be added to the EDTA-tube immediately to
prevent the blood from clotting.
 Commonly used anti-coagulants for hematology are EDTA, Heparin
or Trisodium-citrate.
 Anti-coagulated blood with EDTA.
 The correct dilution of EDTA and blood is very important.
 Differential WBC films and blood films for malaria parasites should
be made within one hour of collecting the blood into EDTA.
 Trisodium citrate is mainly used to coagulation factors tests and to
dilute blood for ESR.

 ESR can be done with EDTA blood but blood must still be
diluted with Tri-sodium citrate.
Universal Precautions:
 Consider all blood specimens as potentially infectious!
 Consider all equipment that has been in contact with blood
specimens as potentially infectious!
 Keep the laboratory clean!
 After work, wipe benches with disinfectant!
 Do not mouth pipette!
 Wear protective coats at all times!
 Do not eat, drink or smoke in the laboratory!
 Cover open wounds with band-aid!
Waste Disposal and Cleaning:
Blood:
 Pour blood into a sink where running water.
 Where running water is not available pour blood into a bucket that
contains 10% bleach solution.
Glass slides:
 Soak glass slides in 5% Phenol solution (e.g. Lysol) at least
overnight.
 Clean and rinse next day.
Needles and Lancets:
 Keep needles in an empty metal container. Burn and bury.
 Boil or autoclave.

Analytical quality control
IQC Procedures: Blood Cells Counting
Total White Blood Cell Count
 Mix the blood and Turk’s solution well before filling the counting
chamber.
 Place the cover slip firmly onto the chamber. You should see
rainbow colors at both sides of the inner rim of the chamber.
 Only use cover slips of the counting chamber do not use ordinary
glass-slips.
 Do not let air-bubbles enter while filling the counting chamber.
 Count the WBC in all four corners of the chamber
 Properly calculate the results.
Differential White Blood Cell Count
 Only examine slides that have an appropriate thickness. See
example!
 Examine the slide at the right place of the slide.
 Count exactly 100 cells before reporting the result.
 Evaluate the RBC morphology.
 Report the morphology of platelets.
Sources of Error
 Improper collection of blood specimens causes variable results.
 Using wet or dirty pipets.
 Not mixing the blood specimen thoroughly.
 Failure to mix anticoagulated blood thoroughly before use.
 Not allowing cells to settle for an adequate amount of time.
 Poor pipetting technique causes high or low counts. Poor pipetting
technique includes:

 Undershooting Unopette with blood.
 Overfilling Unopette with blood.
 Air bubbles in the shaft.
 Failure to expel 3 or 4 drops in the pipet tips before charging the
Hemacytometer.
 Overfilling the chamber of the hemacytometer, that causes
erroneously high counts.
 Not mixing the diluted specimen prior to filling the
Hemacytometer.
 Uneven distribution of cells in the counting chamber causes
erroneous results.
 Counting artifacts.
 Dirty or scratched Hemacytometer.
ESR (Westergren method)
 Correct dilution of blood and EDTA Solution.
 Store Tri-sodium Citrate Solution in the refrigerator.
 EDTA Solution should not be turbid.
 Avoid air-bubbles in the Westergren tube.
 Place the Westergren tube in a vertical position.
 Temperatures above 23 ° C increase the speed of the ESR. Therefore,
keep the ESR rack at the coolest place of the lab and out of direct sun
light.
 Correctly record the exact time, which must be timed for one hour.
Sample Storage and Transportation:
Blood films
 When EDTA blood is used blood films should be prepared within one
hour after collection.

 Store unstained blood films in a dry place and protected from direct
sunlight, dust and flies.
 Stain blood films as soon as possible.
 Keep malaria positive slides in a box for future inspection by the
supervisor.
 Keep doubtful slides in a separate box for inspection by the
supervisor.
 For transportation wrap each slide into a piece of paper and keep it in
a box to avoid breakage.
EDTA anti-coagulated venous blood
 If examination is not possible immediately, store the blood in the
refrigerator at 4 – 8 ° C .
 For most hematological tests, EDTA anti-coagulated blood can be
used for up to 1 week if kept at 4 – 8 ° C .
 Only blood films must be prepared within one hour .
 If transportation is needed transfer the blood into a screw
capped bottle or tube.
 Transport the blood at appropriate temperature .

 Laboratory Skills
o Use a spectrophotometer to perform chemistry
procedures, including
 Correctly setting up the spectrophotometer
 Proper handling, cleaning, and storage of the
spectrophotometer
 Correct use of the wavelength selector
 Proper use of cuvettes
 Recording data from the spectrophotometer
 Constructing a standard curve
 Applying absorbency readings to calculate analyte
concentrations
o Properly prepare reagents, standards, quality control
material, and patient specimens for chemistry
procedures, including
 Preparing working standards from stock standard
solutions
 Proper selection of appropriate glassware
 Proper use of glassware and other laboratory
equipment
 Following written and verbal instructions for
laboratory procedures
o Proper performance of urinalysis testing, including
 Selection of appropriate equipment (conical test tubes)
 Specimen preparation (aliquoting, pre-warming)
 Correct use of a refractometer
 Proper performance of chemical analysis using the
dipstick method
 Correct interpretation of color reactions

 Recording observations and test results
o Troubleshooting and problem solving
 Recognizing errors or discrepancies in results during
lab procedures
 Selecting corrective actions for problem solving
o Use a bright field light microscope to view and interpret
slides during a microscopic urinalysis, including
 Correctly setting up and focusing the microscope
 Proper handling, cleaning, and storage of the
microscope
 Correct use of all lenses
 Recording microscopic observations
o Properly prepare slides for microscopic urinalysis
examination, including
 Specimen concentration (centrifugation, supernatant
removal, sediment resuspension)
 Cleaning and disposing of slides
 Application of specimen to slides and coverslipping
 Cognitive Skills
o Cognitive processes, including
 Formulating a clear, answerable question
 Predicting expected results
 Following written protocols and verbal instructions
o Analysis skills, including
 Collecting and organizing data in a systematic
fashion
 Presenting data in an appropriate form
 Assessing the validity of the data (including integrity
and significance)
 Recognizing errors and developing a corrective
course of action
 Drawing appropriate conclusions based on the results

o Communication skills, including
 Discussing and presenting lab results or findings in
the laboratory
o Interpersonal and citizenry skills, including
 Working effectively in teams or groups so that the
task, results, and analysis may be shared
 Effectively managing time and tasks allowing
concurrent and/or overlapping tasks to be done
simultaneously, by individuals and/or within a group
 Integrating knowledge and making informed
judgments about chemistry test results in the clinical
setting.
 Laboratory Safety
o Laboratory procedures, including
 Reporting all spills and broken glassware to the
instructor and receiving instructions for clean up
 Minimizing or containing the production of aerosols and
describing the hazards associated with aerosols
 Washing hands prior to and following laboratories and at
any time contamination is suspected
 Using universal precautions with blood and other body
fluids and following the requirements of the OSHA
Bloodborne Pathogen Standard
 Disinfecting lab benches and equipment prior to and at
the conclusion of each lab session, using an appropriate
disinfectant and allowing a suitable contact time
 Identification and proper disposal of different types of
waste
 Good lab practice, including returning materials to
proper locations, proper care and handling of equipment,
and keeping the bench top clear of extraneous materials
o Protective procedures, including
 Tying long hair back, wearing personal protective
equipment (eye protection, coats, gloves, closed shoes),
and using such equipment in appropriate situations
 Always using appropriate pipetting devices and
understanding that mouth pipetting is forbidden
 Never eating or drinking in the laboratory

 Never applying cosmetics, handling contact lenses, or
placing objects (fingers, pencils, etc.) in the mouth or
touching the face
o Emergency procedures, including
 Locating and properly using emergency equipment (eye
wash stations, first aid kits, fire extinguishers, chemical
safety showers)
 Reporting all injuries immediately to the instructor
 Following proper steps in the event of an emergency
Below is a list indicating the stability of analytes in serum:
Quality Assurance in Biochemistry
IQC Procedures
General

 Do not examine the specimen, when blood is haemolysed .
 Do not examine the specimen, when the time of the sample collection
is not clear .
 Label the specimen with patient name and lab number to avoid
confusion
 Take great care when pipetting samples and reagents .
 Care for your colorimeter; cover it with a protective cover when not
in use .
 Handle filters with great care.
 Do not touch the filter with fingers, always hold from the side
 Prepare standard curves, whenever you use new reagents or
equipment .
 Use commercially available control sera to control accuracy as
possible.
 Do repeated tests or redo test from the day before, to check your
precision.
 Be careful when repeating and redoing tests; some analytes are not
stable.
 The serum for blood sugar has to be separated from the blood clot
within one hour after the blood collection and the test should be
done within two hours after collection as the concentration of
glucose decreases over time due to glycolysis.
 The arithmetic average of a group of values.
 This is determined by summing the values and dividing by the
number of values.
Standard Deviation
 A statistic which describes the dispersion about the mean.

 The standard deviation is related to the width of a normal curve.
Range
 Range refers to the difference or spread between the highest and
lowest observations.
 It is the simplest measure of dispersion.
Calibrator
 A solution which has a known amount of analyte weighed in or has a
value determined by repetitive testing using a reference or definitive
test method.
Control
 Material or preparation used to monitor the stability of the test system
within predetermined limits.
Internal quality control (IQC)
 ‘internal quality control (IQC) is a set of procedures undertaken by
laboratory staff for the continuous monitoring of operations and the
results of measurements in order to decide whether results are reliable
enough to be released.’
Purposes of Internal quality control (IQC)
 “The main objective of internal quality control (IQC) is to ensure day-
to-day consistency”(WHO 1981)
There are three purposes of IQC:
1. To monitor the accuracy and precision of the complete analytical
process;
2. To detect immediate errors that occur due to test-system failure,
adverse environmental conditions, and operator performance;

3. To monitor over time the accuracy and precision of test performance
that may be influenced by changes in test system performance and
environmental conditions, and variance in operator performance.
Above all, IQC is a control of the precision of your analytical process
with the aim of assuring a long-term constancy of the results. It can also
be a control of trueness depending of the control material used. The main
objective is to ensure the constancy of the results day-to-day and their
conformity with defined criteria.

Quality assurance in medical laboratory

Quality assurance in medical laboratory

Quality assurance in medical laboratory

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