Tabuk University

Tabuk UniversityFaculty of Applied Medical Sciences

Department Of Medical Lab. TechnologyDepartment Of Medical Lab. Technology

3rd Year – Level 5 – AY 1434-1435

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Quality Assurance and Automation in Hematology

By/Dr WalidZAMMITI;

Phd; M.Sc; MLT

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Objectives

Describe the electrical impedance and light scatter principles for performing cell counts.

Utilize quality control procedures to determine if patient results are acceptable.

Explain histograms and their indications. Concentrate on some parameters and indices. Identify the major components of a quality assurance program. Be able to distinguish between quality assurance & quality

control. Define and give examples of each of the following terms:

Accuracy-Calibration-Control-Standard-Precision. Understand the concepts of internal & external control.

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Quality system begins and ends with the patient

Quality Assurance vs. Quality Quality Assurance vs. Quality ControlControl

Quality Assurance

An overallmanagement plan to

guarantee theintegrity of data(The “system”)

Quality Control

A series of analytical measurements used

to assess the quality of the analytical data (The

“tools”)

Quality Assurance in Hematology

QA includes all aspects of laboratory activities that affects the results produced, from the choice of methods, to the education of personnel, to the handling of specimens and reporting results.

The real purpose of QA activities is to determine how correct or incorrect the results emanating from the lab are, and to allow those managing the lab to determine whether or not the lab is fulfilling its functions satisfactorily.

QA in Haematology Laboratory

QA in haematology lab is intended to ensure the reliability of the lab tests.

The objective is to achieve precision and accuracy 4 components of QA programme : 1 ) Internal Quality Control ( IQC )2 ) External Quality Control ( EQC )3 ) Standardization4 ) Proficiency surveillance

Accuracy vs. Accuracy vs. PrecisionPrecision

AccuracyAccuracyHow well a easurement

agrees with an accepted value: is the closeness of the agreement between the result of a measurement and a true value of the measurand.

PrecisionPrecisionHow well a series of

measurements agree with each other: Is the closeness of agreement between independent test results obtained under stipulated conditions.

Accuracy vs. Accuracy vs. PrecisionPrecision

Internal Quality Control

Internal Quality Control Internal quality control is set up within a laboratory to monitor and ensure the reliability of test results from that laboratory.

The primary tool for internal quality control is called a control. A control is a specimen with a predetermined range of result values, called control values, that is processed in the same manner as a patient sample.

Control samples are processed with each series or run of patient samples.

If the result of a test on a control sample is different from its known value, this indicates a problem in the equipment or the methods being used.

External Quality Control ( EQC )

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is the objective evaluation by an outside agency of the

performance by a number of laboratories on material which is

supplied specially for the purpose

is usually organized on a national or regional basis

analysis of performance is retrospective

the objective is to achieve comparability with results of other

labs.

Standardization

Refers to both materialsmaterials and methods.methods. A material standard or reference preparation

is used to calibrate analytic instruments and to assign a quantitative value to calibrators.

A reference method is an exactly defined technique which provides sufficiently accurate and precise data for it to be used to assess the validity of other methods

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Proficiency surveillance

Implies critical supervision of all aspects of laboratory tests: collection, labelling, delivery, storage of specimens before the tests are preformed and of reading and reporting of results.

Also includes maintenance and control of equipment and apparatus.

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Control

 What is a Control?What is a Control?

QC programs require the same sample to be tested QC programs require the same sample to be tested

every day testing is done. every day testing is done.

This type of sample is called a This type of sample is called a controlcontrol. .

Controls, which are often purchased from Controls, which are often purchased from

manufacturers, use a human base to ensure the manufacturers, use a human base to ensure the

analyses being tested parallel human ranges. analyses being tested parallel human ranges.

Manufacturers pool together many human blood Manufacturers pool together many human blood

samples to create the large volume needed for a lot samples to create the large volume needed for a lot

number of controlnumber of control

0102030405060708090

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

+3 sd

-3 sd

+2 sd

-2 sd

-1 sd

+1 sd

Target value

Assay Run

Tools for Validation of QC resultsControl Charts: A Control Chart depend on the use of IQC specimens and is developed in the following manner

Control Charts

Samples of the control specimen are included in every batch of patients’ specimens and the results checked on a control chart

Check precision: it is not necessary to know the exact value of the control specimen

Value has been determined reliably by a reference method, the same material can be used to check accuracy or to calibrate an instrument

Controls with high, low and normal values should be used

Advisable to use at least one control sample per batch even if the batch is very small

The results obtained with the control samples can be plotted on a chart

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How to calculate SDSD

1. Get the Mean.2. Get the deviations. (each value minus the mean)3. Square these.4. Add the squares.5. Divide by total numbers less one.6. Square root of result is Standard DeviationStandard Deviation

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Types Of Errors

An error which varies in an unpredictable manner, in magnitude and sign, when a large number of measurements of the same quantity are made under effectively identical conditions.

Systematic vs.Random Systematic vs.Random ErrorsErrors

Systematic ErrorSystematic ErrorAvoidable error due to controllable variables in a measurement.

Random ErrorsRandom ErrorsUnavoidable errors that are always present in any measurement. Impossible to eliminate

Random Error

Random errors create a characteristic spread of results for any test method and cannot be accounted for by applying corrections. Random errors are difficult to eliminate but repetition reduces the influences of random errors.

Examples of random errors include errors in pipetting and changes in incubation period. Random errors can be minimized by training, supervision and adherence to standard operating procedures.

Random Errors

x

x x

x x

True x x x x

Value x x x

x x x

x

x

x

Systematic Error

An error which, in the course of a number of measurements of the same value of a given quantity, remains constant when measurements are made under the same conditions, or varies according to a definite law when conditions change.

Systematic errors create a characteristic bias in the test results and can be accounted for by applying a correction.

Systematic errors may be induced by factors such as variations in incubation temperature, blockage of plate washer, change in the reagent batch or modifications in testing method.

Systematic Errors

x

x x x x x x x

True x

Value

Automation in Haematology

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Automated techniques of blood counting

Semi-automated instrumentsRequire some steps, as dilution of blood samplesOften measure only a small number of variables

Fully automated instrumentsRequire only that an appropriate blood sample is presented to the instrument.

They can measure 8-20 variables including some new parameters which do not have any equivalent in manual methods.

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The accuracy of automated counters is less impressive than their precision.

In general automated differential counters are favourable to the manual in 2 conditions Exam of normal blood samples Flagging of abnormal samples

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CBC : Complete Blood CountThe complete blood count is performed as an automated

procedure. A sample of blood is placed in an analyzer and the cells are sorted by a laser according to size, granularity, and shape.

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Parameters : Parameters : 1. WBC= Total white blood cells2. RBC= Red blood cell count3. HGB= Hemoglobin concentration4. HCT= Hematocrit (PCV)5.5. MCV= Mean Cell VolumeMCV= Mean Cell Volume6.6. MCH= Mean Cell HemoglobinMCH= Mean Cell Hemoglobin7.7. MCHC= Mean Cell Hemoglobin ConcentrationMCHC= Mean Cell Hemoglobin Concentration8. PLT= Platelets count9.9. NEUT%= Percentage Neutrophil countNEUT%= Percentage Neutrophil count10.10. LYMPH%= Percentage Lymphocyte countLYMPH%= Percentage Lymphocyte count11.11. MONO%= Percentage Monocyte countMONO%= Percentage Monocyte count12.12. EO%= Percentage Eosinophil countEO%= Percentage Eosinophil count13.13. BASO%= BASO%= Percentage Basophil countPercentage Basophil count14.14. NEUT#= Absolute Neutrophil CountNEUT#= Absolute Neutrophil Count15.15. LYMPH#= Absolute Lymphocyte CountLYMPH#= Absolute Lymphocyte Count16.16. MONO#= Absolute Monocyte CountMONO#= Absolute Monocyte Count17.17. EO#= Absolute Eosinophil CountEO#= Absolute Eosinophil Count18.18. BASO#= BASO#= Absolute Basophil CountAbsolute Basophil Count19. RDW-SD= Red cell Distribution Width – Standard DeviationRDW-SD= Red cell Distribution Width – Standard Deviation20.20. RDW-CV= Red cell Distribution Width – Coefficient VariationRDW-CV= Red cell Distribution Width – Coefficient Variation21. MPV= Mean Platelet VolumeMPV= Mean Platelet Volume22.22. PDW = Platelet Distribution WidthPDW = Platelet Distribution Width23.23. Some times other parameters are included; e.g.: Reticulocytes.Some times other parameters are included; e.g.: Reticulocytes.

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Examples of Haematology analysers

1.1. AcT 5diff (Beckman Coulter ) AcT 5diff (Beckman Coulter ) 2. SE 9000, KX21, XE 2100 (Sysmex) SE 9000, KX21, XE 2100 (Sysmex) 3. Advia 60 (Bayer) Advia 60 (Bayer) 4. Cell-Dyn 3500 ( Abott) Cell-Dyn 3500 ( Abott)

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When to Calibrate

You should calibrate your instrument:You should calibrate your instrument:1. At installation.2. After the replacement of any

component that involves dilution characteristics or the primary measurements (such as the apertures).

3. When advised to do so by your service representative.

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Flagging Condition flags

• Describes cell populationnormalabnormal

WBC Suspect flags Blasts Immature Grans/Bands 1 Immature Grans/Bands 2 Variant lymphocytes Review Slide

Check Slide

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Check Slide

More Flagging

RBC Suspect flags NRBCs Macrocytic RBCs Dimorphic RBC population Micro RBCs/RBC fragments RBC agglutination

Definitive Flagging Based on predetermined lab limits Provide information for review

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Histograms

RBC, PLT, and WBC plotted on histogram

X-Axis Cell size in

femtoliters (fL) Y-Axis

# of cells

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RBC Histogram As A Quality Control Tool

INDICATOR PROBABLE CAUSE COMMENTLeft of curve does not touch baseline

Schistocytes and extremely small red cells

Review smear CBC and Platelet histogram

Bimodal peak Transfused cells, therapeutic response

Review Smear

Right portion of curve extended

Red cell autoagglutination

Review CBC & Smear

Left shift of curve Microcytes Review smear & CBC

Right shift of curve Macrocytes Review smear & CBC

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Platelet Histogram As A Quality Control Tool

INDICATOR PROBABLE CAUSE COMMENTPeak or spike at left end of histogram (2-8 fl)

Cytoplasmic fragments

Review smear

Spike towards right end of histogram

Schistocytes, microcytes, giant platelets

Review smear + CBC

( MCV & RDW)

( MPV & PDW)Bimodal peak Cytoplasmic

fragmentsReview smear

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Histograms - WBCs WBC: Distribution with three individual

peaks and valleys at specific regions representing the lymphocytes, monocytes, and granulocytes.

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WBC Histogram As A Quality Control Tool

INDICATOR PROBABLE CAUSE COMMENTTrail extending downward at extreme left, or lymph peak not starting at baseline

NRBC, Plt clumping, unlysed RBC, cryoproteins, parasites

Review smear and correct WBC for NRBC

Peak to the left of lymph peak or widening of lymph peak towards left

NRBC Review smear & correct WBC for NRBC

Widening of lymph peak to right

Atypical lymphs, blasts, plasma cells, hairy cells, eosinophilia, basophilia

Review smear

Wider mono peak Monocytosis, plasma cells, eosinophilia, basophilia, blasts

Review smear

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WBC Histogram As A Quality Control Tool

INDICATOR PROBABLE CAUSE COMMENT

Elevation of left portion of granulocyte

Left Shift Review smear

Elevation of right portion of granulocyte peak

Neutrophilia Review smear

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RDW-SDRDW is an actual measurement of the width of the erythrocyte distribution curve. It is a measurement of AnisocytosisAnisocytosis.May increase before MCV becomes abnormal

Reference values: Reference values: female: 36.4 – 46.3 fLmale: 35.1 – 43.9 fL

It is increased in many types of anemias to indicate the variation in red cell sizes.

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RDW-CV

The coefficient of variation (CV) is defined as the % ratio of the standard deviation (x), to the mean (µ)Cv = x/µSometimes known as relative standard deviation.relative standard deviation.

Reference values: Reference values: female: 11.7 – 14.4%male: 11.6 – 14.4 %

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MCV = MEAN Cell VOLUME M.C.V. = Hematocrit% X 10 RBC in millions/µl Normal values: Normal values: Men & women 82 – 97 fl (femtoliters) = cubic microns Increased : Macrocytes Decreased : Microcytes

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MCH = Mean Cell Hemoglobin

M.C.V. = Hemoglobin g/dl X 10 RBC in millions/µl Normal values: Normal values: Men & women 27 – 32 pg (pico grams) Increased : Hyperchromic Decreased : Hypochromic

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MCHC = Mean Cell Hb Concentration M.C.V. = Hemoglobin g/dl X 100 Hematocrit% Normal values:Normal values: Men & women 30 – 34 g/dl Increased : Hyperchromic Decreased : Hypochromic

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Other Hematology Machines

Coagulometers : - Used in Hemostasis studies, and the Endpoint

Detection depends on Mechanical, Optical (Photo-optical , Nephelometric , Chromogenic or Immunologic), Electrochemical principles.

ESR machines : in 30 minutes. Leucocytes automated Differential

Counters :Using cytochemical or image recognition

methods.

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Thank you

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