Internal Quality Control in Hematology Laboratories

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Nazar Ahmed Mohamed Abd-
Alla(Sangoor)1

c
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Internal Quality control
in Hematoogy
Laboratoreis
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NAZAR AHMED MOHAMED ABD-ALLA
BSC - OMDURMAN AHLIA
HIGH DOPLOMA DGREE - ELZAEM EL-AZHARY
FORMER HEAD OF HEMATOLOGY & BLOOD BANK
MINISTRY OF HEALTH – LABORATORY ADMINISTRATION
KHARTOUM STATE
MARKETING MANAGER-LAB EQP –DIVISION
ALGAM COMPANY FOR DRUGS & CHEMICAL LTD

Topics
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 Quality definition.
 QualityActivity.
 Type of error in clinical Hematology laboratory.
 Specimens and Requests .
 Method selection, and Reagents storage condition .
 instruments and equipment calibration.
 SOPs.
 Use of calibrators and control material .

Topics
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 Implementation of quality programs
 Interpretation of internal quality results.
 Corrective action.
 Turn around time.
 Documentation.

Whats Quality
 quality is defined as the totality of features and characteristics
of a product or service that bear on its ability to satisfy stated
or implied needs.
 Medical laboratories must provide a high quality service by
producing accurate, precise, relevant and comprehensive data
that can be applied to the medical management of patients.
 tests requested must be appropriate to the medical problem,
must be analytically correctly performed and their results
interpreted correctly.
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 Quality assurance:Part of quality management focused on
providing confidence that quality requirements will be
fulfilled . witch contain many activity.
 Quality control:Part of quality management focused on fulfilling
quality requirements.
 Quality management system:Management system to direct and
control an organization with regard to quality.
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 Appropriateness of tests can only be obtained by a dialogue
between the clinician and the medical lab-specialist.
 Correct analytical results are based on:
 (i) quality management within the laboratory.
 (ii) the quality of industrially prepared reagents (kits) and
instruments .
 (iii) quality management of the pre-analytical phase outside
the laboratory along with analytical & post-analytical phase.
 A bad system, a wrong sampling or a kit with poor
performance can never produce a reliable result, even in a
laboratory with the best quality management system.
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principles aspects of making
reliable analytical measurements:
 1.Analytical measurements should be made to satisfy an
agreed requirement.
 2.Analytical measurements should be made using methods
and equipment that have been tested to ensure they are fit
for purpose.
 3. Staff making analytical measurements should be both
qualified and competent to undertake the task.
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principles aspects of making
reliable analytical measurements:
 4.There should be a regular independent assessment of the
technical performance of a laboratory.
 5.Analytical measurements made in one location should be
consistent with those elsewhere.
 6. Organizations making analytical measurements should
have well defined quality control and quality assurance
procedures.
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Quality Assurance
 Quality assurance is a comprehensive and systematic process
that strives to ensure reliable patient results.
This process includes: Every level of laboratory operation.
*Phlebotomy services.
*competency testing.
*error analysis.
*standard protocols.
*quality control.
*turnaround time .
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objective of quality assurance
 1. Lab result must be timely reliable and valid to be used
correctly.
 2. Focus on laboratory staff training and competency.
 3. Give grantee of the reliability of the test result
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Quality assurance requirements
 1. Performance of internal quality control (IQC).
 This is based on the repeat testing of a control sample in each
assay run and then comparison of the assay result with its
expected result.
It is performed in real time and is used to pass or fail a series of
results.
 2.Performance of external quality assessment (EQA)
this based on a sample that is sent to a group of laboratories.
The relative position of the laboratory in relation to the others is
calculated retrospectively.
In combination, IQC and EQA can monitor both precision and
accuracy.
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*QA activities encompass all of the non-analytic activities,
those activities that are not part of the clinical testing
process.
*The laboratory organizes it activities to provide the best
possible health care to the patient.
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QA activities
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* A. management and monitoring personnel,
B. using quality materials (reagents instruments, supplies, etc.),
C. using established procedures and established statistics (a
procedure manual),
D. specimen collection, identification, transport, accession, and
handling prior to testing,
E. reporting results,
F. fee charges for tests performed,
G. using corrective actions to obtain desired results,
H. monitoring patient satisfaction.
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Examples of QA Activities
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*The Clinical laboratory is concerned about quality and
accuracy of the tests that are reported to primary care
givers.
*The laboratory monitors where these errors can appear
that will affect the accuracy of test results.
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NON-CONFORMING RESULTS
 In laboratory practice many non-conforming results may
appear.
These results are divided in two major categories:
 • 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.
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*These errors can occur prior to the test analysis and if they
manifest, they are called preanalytical errors or variables.
*If the error occurs during the testing process, then it become an
analytical error.
*If the error appears after the test is performed and reported, then
it is known as a post-analytical error.
*The preanalytical error occurs before the test is performed. This
error source can occur at the beginning of test ordering and
filling out the requisition.
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Type Of Error
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*type of error based on the time
*Pre-Analytical Error:(specimen collection and transport)
01- duplicate or missing requisitions
02- tests omitted from the requisition
03- incorrect ordering of tests
04- patient identification error
05- incorrect blood collection
06- specimen transport error
07- specimen handling/processing in the lab
*Analytical errors: (specimen processing in the lab)
occur during the testing process.
01- deteriorated or wrong reagents
02- any instrument malfunction
03- laboratorial error
04- incorrect recording of test results

* Post Analytical Error:(reporting and interpretation of
results)
* Examples of these are:
01- failure to notify the physician of critical values: (Critical
values may imply a life-threatening situation for the patient and
are brought to the immediate attention of the physician and/or
the patient care area responsible for the patient ).
02- failure to report test results in a timely manner.
03- placement of report in the chart of the wrong patient
04- miscommunications that are detrimental to the patient
regarding the tests performed.

Pre-Analytical Error
Specimens and Requests
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1- Request forms:
 Request forms should include:
 Organization name and full address and telephone ,fax number & E.mail.
 Referring doctor name and telephone number.
 Patient details.(age,sex,race,resedance)
 Specimen details .(type,preservatie,time of collection)
 Clinical Remarks .(spleenomegaly,hepatomegly,fever,join pain)
 Treatment history (any type of medication e.g asprine,sulfanomide;ect).
 Tests ordering.(CBC,Urine general,lipid profile ………….. Ect)
 Signture of cliniciant order the test.

2- Primary sample collection:
• 1- Patient Preparation:
*Avoiding stress and exercise witch increase
Cell concentration, coagulation factors(v111),tissue
plasminogen activator(T-PA) with increase fibrinolytic
activity).
*Avoid prolonged use of tourniquet. and patient
position (lying or standing to avoid
haemoconcentration) also position of the arm witch
cause fluctuation of about 5-10% in the blood count .
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Alla(Sangoor)
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2-Containers selection and type of anticoagulant:
e.g the most suitable one for haematology is K₂EDTA in
concentration of 1.2-2.2mg/ml witch cause less cellular
change(recommended by ICSH).
K₃EDTA also can used but it cause significant shrinking of the
red call with decrease of about 1-2%in the MCV.
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*other Example is the amount of sodium citrate
when the amount of citrate is high and the
amount of blood is low the excess sodium
citrate consume ca²+ present in the reagent.
& this prolong the PT&APTT.
the opposite case lead to microclot as a matter
this Couse shortness of APTT

3-BloodCollection:
way of collecting the sample (venous blood or capillary
blood)
in capillary blood improper technique can cause (presence
of micro clots or platelets clumps low platelets count
reported by cell counter.
Also delay sample lead to factor deterioration witch lead to
prolongation of PT &APTT(in coagulation)
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•*Avoid dilution and or contamination from flushing solution while
drawing the blood from indwelling line or catheter.
•*(Contamination with heparin couse prolongation of APTT (in
coagulation))
* When intravenous solution is being administrate in patient arm
the blood drawing should be from the opposite arm

 The recommended order of draw is:
 • Blood culture tube
 • Coagulation tube
 • Serum tube with or without clot activator, and with or without
gel separator
 • Heparin tube, with or without gel separator
 • EDTA tube
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6-Specimen storage andTransportation:
*for sample transport : (tray should have protective cover ,
suitable environment require preventing deterioration of the
sample , person carrying the sample should be follow the
universal safety regulation.
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: mislabeling of sample is very seriouslabeling of the sample-4
error witch can result as:( collecting from wrong patient ,
subsequent specimen mix –up , transcription error)
Plasma Preparation:-5
spaciely in case of coagulation the preparation of the plasma is
very critical.
•The accepted goal of centrifugation of coagulation specimens
is to produce platelet-poor plasma with a platelet count <
10×10⁹ /L< 10×10³/L1.
•* This may be accomplished by centrifuging specimens at
1500 g for 15 minutes or longer at room temperature.

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3- Samples acceptance criteria:
 Complete request form.
 Patient identification.
 Suitable container selected.
 Sufficient amount of blood collected.
 Sample labeled properly.
 Sample prepared properly.
 Sample separated and store properly.

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4-Samples Rejection Criteria:
 Incomplete request form.
 Rung Patient identification.
 Unsuitable container selected.
 Unlabelled or incorrectly labeled sample.
 Haemolysed sample.
 Sample changes due to :
 concentration changes
 compostion changes.
 bacterail changes.
 and enzymatic changes.

Analytical errors
METHOD VALIDATION
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 Validation refers to establishing documented evidence that a process or
system, when operating within established parameters, can perform
effectively and reproducibly to produce a result meeting its
predetermined specifications and quality attributes.
 “Method validation” is a term used for the suite of procedures to which
an analytical method is subjected.
 to provide objective evidence that the method, if used in the manner
specified, will produce results that conform to the statement of the
method validation parameters.

ISO Definition
 1.The process of establishing the performance characteristics
and limitations of a method and the identification of the
influences which may change these characteristics and to
what extent.
 *Which analytes can it determine in which matrices in the
presence of which interferences?Within these conditions
what levels of precision and accuracy can be achieved?
 2.The process of verifying that a method is fit for purpose,
i.e. for use for solving a particular analytical problem.
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Continue: Method validation
 Method validation involves the evaluation of the fitness of
analytical methods for their purpose.
 The process of proving that an analytical method is
acceptable for its intended purpose.
 the concept of fitness for purpose, a method is validated for
a particular use under particular circumstances. If those
circumstances vary, then the method would need to be re-
validated at least for the differences.
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METHOD VALIDATION
 Error assessment is what method validation is about.
 However, before getting to the assessment of errors, you
have to first select the method to be validated.
 Method selection is a different process that needs to be
understood in relation to the validation process that will
follow.

Importance of Method Validation Practices
 Laboratory regulations require that method performance for
any new method be "verified" prior to reporting patient test
results.
 Precision and accuracy are specifically identified, along with
analytical sensitivity, analytical specificity, reportable range,
reference values, and any other applicable characteristic.

Types of Errors to be assessed by
method validation
 Errors based on the stage
 imprecision or random errors,
 inaccuracy, bias, or systematic errors, which can be of two
types
 *constant systematic error or
 *proportional systematic error.
 All these errors can be recognized when a group of
measurements are compared to the correct or true values.

Verification
 Verification refers to the ability to make sure that the test
method you are using conforms to manufacturer
specifications.
 Much of the work of method validation is done by
international organizations that publish standard methods.The
reason such methods appear to be written in a kind of legalese
is that there must be no doubt as to what the method is and
how it should be implemented.
 *When accuracy and precision data are published from
interlaboratory trials, there is some confidence that the
method has undergone extreme scrutiny and testing.
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Verification
 A laboratory that uses a method for the first time should spend
some time in going through the analysis with standard materials
so that when used with field samples, the method will yield
satisfactory results.
 This is verification and must be done to an appropriate level
before any method is used. By its nature, (verification comes
under the heading of Single LaboratoryValidation).
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Method performance parameters assessed
in a method validation study
 Identity: Measurement correctly applies to the stated measurand.
 Selectivity Specificity: Determination of the extent of the effects
of interfering substances and the ability of the method to measure
the measurand; analysis in different matrices covered by the scope
of the validation.
 Limit of detection: Minimum value of the measurand at which the
presence of the analyte can be determined with a given probability
of a false negative, and in the absence of the analyte, at a given
probability of a false positive.
 [Limit of determination] Minimum value that can be obtained
with a specified measurement uncertainty
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 Calibration [linearity] Model parameters [sensitivity] :Adequacy
of the calibration model; parameters with uncertainties.
 Calibration range [linear range] Range of values of the
measurand in which the validation holds
 Bias and recovery [accuracy] :Demonstration of the absence of
significant systematic error after corrections have been made for
bias and/or recovery
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 Robustness or ruggedness:Ability of method to remain
unaffected by small variations in method parameters (some
authors make the distinction bebetween the property
robustness and a ruggedness test in which deliberate changes
are made in a method to assess the robustness)
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Method Selection
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1. General Characteristics:
Made in ,Expire date, Package Content,Accessories, Package
size ,Stability after open, and Reagent storage considerations.
2. Application Characteristics:
Specimen type, Sample volume,TurnaroundTime, Stability of
reaction product, Cost-per-test, Filter used, and Safety
considerations
3. Methodology Characteristics:
Type of Reaction, Reaction Principle, Measurement reaction,
Temperature, andTime period of measurement.

Experiments for estimating analytical errors

METHOD COMPARISSION FOR HBG
ESTIMATION BETWEEN TOW DIFFERENT
INSTRUMENT
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0
2
4
6
8
10
12
14
16
18
0 2 4 6 8 10 12 14 16 18 20
HBG
HBG

METHOD COMPARISSION FOR HBG ESTIMATION
BETWEEN TOW DIFFERENT INSTRUMENT
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0
2
4
6
8
10
12
14
16
18
20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
medonic HBG
mindrays HBG

METHOD COMPARISSION FOR HBG ESTIMATION
BETWEEN TOW DIFFERENT INSTRUMENT
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0
2
4
6
8
10
12
14
16
18
20
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
medonic HBG
mindrays HBG

Micropipettes Calibration
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 Gravimetric method (Distilled waterweighing method)
(Recommended method)
 Work Requirement:
1. Calibration tools
2. Double distilled water.
3. New compatible tip
4. Analytical electronic balance(3-5 digits)
5. Temperature controlled atmosphere
6. Small plastic beaker.

Checking Micropipettes Calibration
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 Weighing Should takes place at 20-25ċ constant to ± 0.5ċ.
 Set the desire testing volume of your pipette.
 Carefully fit the tip onto the tip cone.
 Aspirate the distilled water 5 times( Humidity equilibrium
 Carefully aspirate the fluid, keeping the pipette vertical.
 Pipette distilled water into a tred container and read the
weight in mgs.
 Repeat at least five times (ten times )and record each
result in mgs.

Checking Micropipettes Calibration
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 Convert the recoded weight to volume (V1) either
by divide the weight of the water by its density ( at
20ċ : 0.9982 ) or by multiply the weight by the Z
correction factor (= 1.002899 µl/mg at 20Ċ ).
 Calculate the mean volume (V1)
 Calculate the standard d deviation SD.
 Calculate the Coefficient of Variation.
 Calculate the Inaccuracy and Imprecision .
 Calculate the F max value.

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Standard Operating Procedures
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SOPs are written , up to date instructions and information
which cover in details how to perform individual tests to
insure the correct use , availability , reliability , timeliness,
and reporting of blood tests and correct interpretation of the
test result

*Quality control (QC) encompasses quality assurance as it
focuses on analytical activities that are associated with the
testing process. QC consists of:
A. running control samples with patient samples,
B. using established statistical methods to determine
reliability of test procedures and test results,
C. monitoring instrument and laboratorial performance.
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Quality control
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Quantitative QC Materials
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 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

Sources for Control Materials
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 Commercial product.
 Diagnostic samples (qualitative QC).
 “Homemade” or “In-house”.
 Obtained from:
Another laboratory .
EQA provider.

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Parallel Testing.-Validation of new controls
*Whenever possible, new lots of control material must be assayed
in parallel alongside the current in use lot.
*This is to enable the calculation of laboratory QC ranges and to
demonstrate that the QC material is performing as expected.

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Controls for Quantitative Assays:
a. In order to validate new controls, the new lot of controls
will be run in parallel with the old lot of controls 2-3 times a
day for 5-10 days, to give a minimum of 20 values to enable
the calculation of laboratory specific QC ranges. The mean
and QC ranges for the new lot of controls will be reviewed
and signed off by the laboratory supervisor or director
before being put into use.

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b. For hematology the new lot of controls should be
run in parallel with the old lot of controls to give a
minimum of 10 values over a period 5 days if possible.
The mean and ranges for the new lot of controls will
be reviewed and signed off by the laboratory
supervisor or director before being put into use.

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Controls for Qualitative Assays:.2
Each new lot of QC for qualitative assays must be run
and give an expected response. The lot of controls will
be reviewed and signed off by the laboratory
supervisor or director before being put into use.

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Types of Control Materials
 Assayed
mean calculated by the manufacturer
must verify in the laboratory
 Unassayed
less expensive
must perform data analysis
 “Homemade” or “In-house”
pooled sera collected in the laboratory
characterized
preserved in small quantities for daily use

Levey-Jennings Chart
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o A graphical method for displaying control results and
evaluating whether a procedure is in-control or out-of-control
o Control values are plotted versus time
o Lines are drawn from point to point to accent any trends,
shifts, or random excursions

Levey-Jennings Chart
 control sample included in each assay run
 data plotted graphically (assay value verses time
 of day)
 control (or confidence) limits
 mean
 standard deviation (usually + 2 SD)
 if control limits are not met, then no patient
samples run in that batch can be reported.
 if control limits are met, then patient samples run
in that batch can be reported
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QC changes detectable with Levey-
Jennings plots
 Drift: control value moves progressively in one
direction from the mean for at least 3 days e.g
deterioration of reagent or control
 Dispersion :increase in random errors e.g
inconsistency in technique
 Shift: sudden problem develops e.g instrument
malfunction or technique change
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Findings Over Time
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Ideally should have control values clustered about the mean
(+/-2 SD) with little variation in the upward or downward
direction
Imprecision = large amount of scatter about the mean.
Usually caused by errors in technique
Inaccuracy = may see as a trend or a shift, usually caused by
change in the testing process
Random error = no pattern. Usually poor technique,
malfunctioning equipment

Levey-Jennings Chart -
Record and Evaluate the Control Values
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80
85
90
95
100
105
110
115
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD

What are the "Westgard rules”
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They are different combination of rules depending on the number
of control being used, the total allowable error, and your work
environment.
rulesThat are used as conjunction with each other to provide a
high level of errors detection, while reducing the incidence of
false rejection.

Typical rules combination
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 For control run in multiples of 2 “ typical chemistry”
 13s / 22s / R4s / 41s / 10 x
 For control run in multiples of 3“ typical
haematology,coagulation, and immunoassays”.
 13s / 2 of 32s / R4s / 31s / 12 x

Westgard Rules
(Generally used where 2 levels of control
material are analyzed per run)
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 12S rule
 13S rule
 22S rule
 R4S rule
 41S rule
 10X rule

Westgard – 12S Rule
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 “warning rule”
One of two control results falls outside
±2SD
Alerts tech to possible problems
Not cause for rejecting a run
Must then evaluate the 13S rule

12S Rule = A warning to trigger careful inspection of
the control data
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
12S rule
violation

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If either of the two control results
falls outside of ±3SD, rule is
violated
Run must be rejected
If 13S not violated, check 22S

13S Rule = Reject the run when a single control
measurement exceeds the +3SD or -3SD control limit
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
13S rule
violation

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2 consecutive control values for the same level fall outside
of ±2SD in the same direction, or
Both controls in the same run exceed ±2SD
Patient results cannot be reported
Requires corrective action

22S Rule = Reject the run when 2 consecutive control
measurements exceed the same
+2SD or -2SD control limit
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
22S rule
violation

Westgard – R4S Rule
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One control exceeds the mean by –2SD, and the other
control exceeds the mean by +2SD
The range between the two results will therefore exceed 4
SD
Random error has occurred, test run must be rejected

R4S Rule = Reject the run when 1 control
measurement exceed the +2SD and the other exceeds
the -2SD control limit
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
R4S rule
violation

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o Requires control data from previous runs
o Four consecutive QC results for one level of control are
outside ±1SD, or
o Both levels of control have consecutive results that are outside
±1SD

41S - reject when 4 consecutive
control measurements exceed the
same mean ± 1s limit.
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Westgard – 10X Rule
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 Requires control data from previous runs
 Ten consecutive QC results for one level of control are on
one side of the mean, or
 Both levels of control have five consecutive results that are on
the same side of the mean

10x Rule = Reject the run when 10 consecutive control
measurements fall on one side of the mean
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Mean
Day
+1SD
+2SD
+3SD
-1SD
-2SD
-3SD
10x rule
violation

Moving Averages (Bull’s method)
 large laboratories (built into blood analysers) assumes the
population sampled each day remains constant
 therefore the calculated indices (MCV, MCH and MCHC)
remain stable
 determine mean indice values for each batch of 20 patients,
plot on control chart
 any change: instrument or technical fault
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Moving Averages (Bull’s method)
 For the interpretation of Bull’s charts two rules have been
proposed
 13%. Bull’s moving average exceeds the limit ± 3%.
 32% .The mean value of three successive Bulls’ moving
averages exceeds the limit ± 2%.
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Moving Averages
 MCV = Hct
RCC
 MCH = Hb
RCC
 MCHC = Hb
Hct
 Changes in the moving
averages graphs indicate
where the problem
might be in the system.
eg. If the light source
for Hb is becoming
weak, then the
calculated MCH and
MCHC values will fall
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Moving averages
 CAUSE MCV MCH MCHC
 LowHb no change low low
 High Hb no chang high high
 Low RCC high high no change
 High RCC low low no change
 Low Hct low no change high
 High Hct high no change low
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Duplicate tests on patient samples
 tests precision
 will not detect incorrect calibration
(accuracy)
 smaller laboratories
 METHOD
 test 10 samples
 repeat the tests
 calculate the difference between pairs of results
and derive a standard deviation
 SD should always be < 2SD
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Check tests on patient samples
 monitors day-to-day precision (small lab)
 detects deterioration within apparatus and
reagents
 METHOD
 » select 3-5 normals in the afternoon, record and
average values (WCC, RCC, Hb). Store at 4oC.
 » re-assay same samples next morning
 » tests should agree within 2SD
 Must ensure there has been no change in samples
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Delta check method
 Delta check is the difference between the current value of one person and
the previous one.
 Delta check = Current value – Previous value
 Delta check% = (Current value – Previous value) 100/Current
value .
 Delta check detect random errors using previous values of
individual patient.
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Delta check
 reasons of delta differences:
 1.The “intra-individual” biological variation of the analyte
 2.The analytical variation ,
 3.The pre-analytical variation .
 4.The improvement or deterioration of the patient’s health.
 5. Errors and mistakes in the pre-analytical, analytical and
post-analytical stage.
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Corrective action
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 Errors assessment and management:
 Change Old Habits - Recognize Problems.
 Bad habit Repeat the control .
 Inspect the control charts or rules violated to determine
type of error.
 Relate the type of error to potential causes.
 Consider factors in common on multitest systems
 Relate causes to recent changes
 Verify the solution and document the remedy

POST ANALYTICAL
 1-Written of the report in satnder format :
 2- Delta check :the blood count parameters should not differ from
recent test in the previous 2-3 weeks by more than a certain amount.
assuming that the patient clinical condition has not altered
significantly.
 -For HBG & RBC 10%.
 -ForWBC 20-25%.
 -For Platelets 50%.
 3-Alert the clinician the critical values:
 HBG ˂ 6 , Platelets ˂ 1000cell/cumm ,INR ˃ 2 ,APTT ratio ˃ 2
 Peripheral blood picture: presence of malaria & or blast cells
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4- Turn around Times (TATs):
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 Laboratory test turnaround times (TATs) In contrast to
laboratorians, the majority of clinicians defined aTAT start time
as test ordering, and aTAT ending time as result reporting.
 Timely reporting of patient tests can increase efficiency of care
and improve customer satisfaction.
 In study done 2008 found that postanalytical phase accounted
for 64-88% of total tumround time, the pre-analytical phase
for 7-17%, and the analytical phase for 2-29%.

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Sample post analytical
 Sample retention:
 If needs to repeat the examination.
 In case of requested other infestigatione.
 Sample diposale: the sample dispose according to
specification.
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Definitions
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*Forms: Blank form design to special work to be fill by data at
time of use.
*Records: worksheets, forms, charts, labels, Used to
capture information, activities, or results when performing a
procedure
*Documents: written policies, process descriptions,
procedures, and forms Used to communicate information
 May be paper or electronic

Documents and Records
• Document control policy
– Creation, review, and modifying documents and records and forms
• Procedures, processes, and policies
– Format,
– Approval process
– Flowcharts
• Records retention and disposition
– How long to retain records
– How to dispose of records
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External quality control (EQC)
 External quality control or external assessment scheme
(EQAS) or proficiency testing program (PT):
 refer to the process of controlling the accuracy of an analytical
method by interlaboratory comparisons.
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BASIC IDEA OF EQAS
 1.The EQAS coordinator prepares and sends to the
participants of the scheme one or two samples from the same
pool.
 2.The samples are assayed by the laboratories using the same
equipment and reagents as they do in routine for the patients’
determinations.
 3.The EQAS coordinator gathers all the results and it groups
them (peer groups) according the laboratories analytical
methods, analyzers or any other criteria.
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BASIC IDEA OF EQAS
 4.The EQAS coordinator calculates the target value
(consensus mean) and its total variation (expressed as
standard deviation) of the laboratories results.
 5. If any of the laboratories has values outside of the control
limits (target value ± allowable variation) then this laboratory
is considered “out of control”.
 6.The “out of control” laboratories have to correct their
analytical procedures.
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 EQAS has its own charts and statistics.
 One of the most important statistics is the “Standard
 Deviation Index” (SDI).
 SDI shows the distance of the laboratory results from the
consensus mean. It quantifies the inaccuracy of the analytical
method.
 It is similar to Z-score (equation ) and it is calculated by the
formula:
SDI = laboratory result -Mean value of peer group
Strandard deviation of peer group
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Four rules are usually employed for SDI evaluation
 1- 2/51SDI.Two from five successive control limits exceed
1 SDI. It is a warning rule.
 2- X1.5 SDI . The mean value of five SDI values exceeds the
limits ±1.5 SDI. It reveals a lasting systematic error.
 3-13SDI. One value exceeds the limits ±3 SDI.
 4- R4SDI. The range (R) between the lower and higher SDI
values is over ±4 SDI.
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Precision Index and Coefficient of Variation
Ratio (CVR)
 External quality assessment schemes quite often use two
different statistics for the measurement of precision, the
Precision Index (PI) and the Coefficient ofVariation Ratio
(CVR).
 PI = Standard deviation of laboratory
Strandard deviation of peer group
The control limits of PI are < 2.
 CVR = CV of laboratory /month
CV of peer group/ month
 The combined SDI/CVR chart has the ability to evaluate the
total analyte’s performance(precision and accuracy).
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SUMMARY
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 Pateint preparation, and good specimen collection,
preparation , handling, and storage of specimen.
 Clinical Laboratory instruments daily, weekly, and monthly
maintenance and calibration done regular.
 Micropipettes recalibration takes place monthly .
 Good clinical method selected, and Reagents storage
condition verified by monitoring of refrigerators
temperature.

SUMMARY
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 SOPs written, approved ,and followed carefully, then Sops
critical point check list used daily.
 MORE than one levels of control sera at least should used in
all batches with patient samples.
 Results of control sera register in quality book and blotted
in levey Jennings chart.
 Westgard rules used as guidance for acceptability or
rejection of patient results applied.
 Errors assessment and management takes place, and
corrective action documented.
 Turn a round time to all investigation verify monthly.
 Documentation (to all lab activities)

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Internal Quality Control in Hematology Laboratories

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