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ب وام خدا

Dr. K. Khodaverdian

Reference Health Laboratory

Quality Assurance in Heamatology

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Quality

“Quality is doing the right things

and doing those things right”

“ Quality is everyone’s responsibility”

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WHAT IS QUALITY???

• Quality Control (QC)

• Quality Assurance (QA)

• Continuous Quality Improvement (QI)

• Quality System

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Quality Control vs. Quality Assurance

Quality Control is method control

Quality Assurance is process control

Quality System is the process of building quality into the entire system

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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 Assesment( EQA )

3 ) Standardization

4 ) Proficiency surveillance

The ultimate goil of quality system is to obtain test results

that are Reliable, relevant, reproducible&

As accurate as possible

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What is Quality Control?

• Process or system for monitoring the quality of laboratory testing, and the accuracy and precision of results

• Routinely collect and analyze data from every test run or procedure

• Allows for immediate corrective action

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Pre-Analytical Analytical Post-Analytical

Quality Control

(QC)

QUALITY ASSURANCE (QA)

Quality Control (QC): measures that must be included during

each assay to verify that the test is working properly.

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The Quality Assurance Cycle

•Data and Lab

Management

•Safety

•Customer

Service

Patient/Client Prep

Sample Collection

Sample Receipt

and Accessioning

Sample Transport Quality Control

Record Keeping

Reporting Personnel Competency

Test Evaluations

Testing

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The Quality Assurance Targets • Pre analytical Process

Pat. preparation Specimen collection, Anticoagulant ,Labeling ,Storage,

Transportation • Analytical Process

Test method/procedure, Reagant IQC,EQC

• Post analytical Process Review of Pat. Results ,Posting of Pat. Results Maintenance of Pat.records Maintaining of all documents

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Designing a QC Program –

• Establish written policies and procedures

Corrective action procedures

• Train all staff

• Design forms

• Assure complete documentation and review

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Measures of Central Tendency

• Mean = the calculated average of the values

• Median = the value at the center (midpoint) of the observations

• Mode = the value which occurs with the greatest frequency

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Calculation of Mean

X = Mean

X1 = First result

X2 = Second result

Xn = Last result in series

n – Total number of results

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Calculation of Mean

1) 126

2) 120

3) 118

4) 124

5) 115

6) 110

7) 112

8) 115

9) 122

10) 120

11) 115

Sum=1297

• Mean = the calculated average of the values

• The sum of the values (X1

+ X2 + X3 … X11) divided by the number (n) of observations

• The mean of these 11 observations is 1297 11) = 117.9 g/L

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Measures of Dispersion

or Variability

• There are several terms that describe the dispersion or variability of the data around the mean:

Range

Variance S2 = ∑ (X-X)2

n-1

Standard Deviation √ S2

Coefficient of Variation SD /mean x100

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Normal Distribution

• All values are symmetrically distributed around the mean

• Characteristic “bell-shaped” curve

• Assumed for all quality control statistics

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• Normal Distribution Curve

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Accuracy and Precision

• The degree of fluctuation in the measurements is indicative of the “precision” of the assay. (reproducibility)

can be controlled by replicate tests, check tests on previously measured specimens and statistical evaluation of results

The quantification of precision is measured by CV , Indicator of Random error

• The closeness of measurements to the true value is indicative of the “accuracy” of the assay. can be checked by the use of reference materials

The quantification of accuracy is measured by mean

• Quality Control is used to monitor both the precision and the accuracy of the assay in order to provide reliable results.

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Accuracy vs. Precision

Accuracy

How well a measurement agrees with an accepted value

Precision

How well a series of measurements agree with each other

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• Precise and inaccurate • Precise and accurate

Precision and Accuracy

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Imprecise and inaccurate

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Standard Deviation and Probability

• For a set of data with a normal distribution, a value will fall within a range of:

+/- 1 SD 68.2% of the time

+/- 2 SD 95.5% of the time

+/- 3 SD 99.7% of the time

68.2%

95.5%

99.7% F

req

uen

cy

-3s- 2s -1s Mean +1s +2s +3s

X

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Standard Deviation and Probability

• In general, laboratories use the +/- 2 SD criteria for the limits of the acceptable range for a test

• When the QC measurement falls within that range, there is 95.5% confidence that the measurement is correct

• Only 4.5% of the time will a value fall outside of that range due to chance; more likely it will be due to error

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Analysis of Control Materials

• Need data set of at least 20 points, obtained over a 30 day period

• Calculate mean, standard deviation, coefficient of variation; determine target ranges

• Develop Levey-Jennings charts, plot results

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Levey-Jennings Chart

-2 0 -1 5 -1 0 -5 0

+3SD

+2SD

+1SD

Mean

-1SD

-2SD

-3SD0

0.4

0.8

1 .2

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Levey-Jennings Chart

• A graphical method for displaying control results and evaluating whether a procedure is in-control or out-of-control

• Control values are plotted versus time

• Lines are drawn from point to point to accent any trends, shifts, or random excursions

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Levey-Jennings Chart - Record and Evaluate the Control Values

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

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Internal Quality Control

• Levey-Jennings Control Chart

1. Degree of scatter or impression

2. Shift is a drift in values, may be sudden

3. Trend is continuous movement of values in one direction for 6 or more consecutive values (slowly development)

4. A trend may be thought of as a gradual shift

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Trend

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Shift

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Westgard Rules

(Generally used where 2 levels of control

material are analyzed per run)

• 12S rule

• 13S rule

• 22S rule

• R4S rule

• 41S rule

• 10X rule

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Westgard – 12S Rule • “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

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Westgard – 13S Rule • If either of the two control results falls outside of

±3SD, rule is violated

• Run must be rejected

• If 13S not violated, check 22S

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Westgard – 22S Rule • 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

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Westgard – R4S Rule • 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

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Westgard – 41S Rule • Requires control data from previous runs

• Four consecutive QC results for one level of control are outside ±1SD, or

• Both levels of control have consecutive results that are outside ±1SD

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Westgard – 10X Rule • 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

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Westgard

1 2s2 SD±

1 3s3 SD±

2 2s2SD±

R 4s2 SD

2 SD

4 1s1 SD

1 SD

10 x

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Implementing a QC Program –

Quantitative Tests • Select high quality controls • Collect at least 20 control values over a period of

20-30 days for each level of control • Perform statistical analysis • Develop Levey-Jennings chart • Monitor control values using the Levey-Jennings

chart and/or Westgard rules • Take immediate corrective action, if needed

Record actions taken

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When a rule is violated

• Warning rule = use other rules to inspect the control points

• Rejection rule = “out of control”

Stop testing

Identify and correct problem

Repeat testing on patient samples and controls

Do not report patient results until problem is solved and controls indicate proper performance

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Errors • Systematic Errors (bias, shifts&trends) – affect the

accuracy of system

Usually 22S,,, 41S, 10X rules

Can be due to: change in reagent or calibration lot ,wrong calibrator value, improperly prepared reagent ,inadequate storage of reagent or calibrator, deterioration of reagent or calibrator temperature change in incubator unit, deterioration of photometric light source

Systemic errors are most often related to

reagent or calibration problems

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Errors

• Random errors-these errors affect the the reproducibility of precision of a test system.

Usually 12S,13S,R4S Rules

Can be due to bubbles in reagents& reagent line s ,Inadequately mixed reagents unstable Tem. &incubation, individual operator variation in pipetting….

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Quality assurance programme

a)At all time:

*Correlation system

-Blood film with blood count

-Blood count with clinical data

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Quality assurance programme

• At all times Correction system

*Correction of blood film appearances with blood count

WBC(obj40) x 2000 WBC count

PLT (obj100) x15000 PLT count

MCV →micro/macro

MCHC →hypo/hyper

HCT= Hbx3 / Hb= RBCx3 / HCt=RBCx9

*Correction of blood count changes with clinical events

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Quality assurance programme

• Daily

Test on control specimen ,control chart

Duplicate test s on a few of patients Spec.

Check test on a few patients from a previous batch

Delta Test

Daily mean

Calibration Verification ( T - Brittin)

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Quality assurance programme

• Daily

Test on control specimen ,control chart

Duplicate test s on a few of patients Spec.

Check test on a few patients from a previous batch

Delta

Daily mean

Calibration Verification (T- Birittin)

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Duplicate test Specimen 1st count 2st count d d2

1 5.4 5.8 0.4 0.16 2 8.3 10.5 2.2 4.84 3 17.2 18 0 .8 0.64 4 5.4 5.4 0 0 5 12.2 11.8 0.4 0.16 ∑d2=5.8 SD=√ d2/2n SD=0.76 2sd=1.5

none of the duplicate tests should differ from each other more than 2SD

*d> 2SD → random error

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Check test • Similar to duplicate test but use specimen with

have been measure originally in an earlier batch

• The test should agree with each other with 2SD

• Detection deterioration of apparatus and reagent between tests

• Suitable for Hb &RBC less for WBC &PLT

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Delta test

• Comparison of current results with a recent previous result on the same patient

Hb <10%

RBC <10%

WBC <20%

PLT <50%

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Daily Mean (Bull’ s method)

• In hospital over 100 test request each day , there should be no significant daily variable in the means of red cell indices Automation : MCV,MCH,MCHC Analyse the results in successive batches of 20 specimens

By plotting this results on graph, any drift from 3 indices can be readily recognized and used to identify instruments faults

Manual : MCHC

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Calibration Verification

بب تج ب پبیذاری پبرايتر ب اذکص بی خ يحيغی •درج يی تا از آزي 4ضبػت در ديبی 24ب يذت . جت کترل کيفی اضتفبد د T-Brittinآيبری

) (T=2.26 10ترجيحب ) T=2.78) 5حذالم •

Sd =√ ∑(d2)- (∑d)2 /n / n-1

√nd = tn SD

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Quality assurance programme

• At intervals Initially and when indicated

calibration of pipetts &automatic dispensers

• At intervals Initially & at least six monthly

Photometer ,spectrophotometer

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فرايىد قبل از آزمايص

جغ آری

ضذ اؼمبد يبضب

يؼيبربی رد لبل

غرایظ گ داری

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تجيسات ضبتریفژ•

ييکرضبتریفژ•

غبرذ ضهنی خدکبر•

فتيتر •

(مدرک)ضىاسىام -

(مدرک)دسترالعمل فىی-

سابق کىترل کيفی وگ داری-

سابق سريس تعمير -

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دستگاي ضمارودي سللی يذارک

غبضبي @ تبریخ خریذ -•

تبریخ صب ، کبنيبراضي بو فرد را اذازی کذ- •

تبریخ غرع بکبر دضتگب -•

کبرخب کػر ضبزذ -•

يذل غبر ضریبل دضتگب -•

( ، يطتؼم ، ببزضبزی غذ )غرایظ دضتگب گبو خریذ -•

بو ، غبر تهم آدرش غرکت پػتيبب -•

بو کبربر یب کبربرا دضتگب-•

يػخصبت کبربر ح آيزظ کبربر دضتگب تضظ غرکت پػتيبب -•

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ضىاسىام تجيسات

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ضمارضگرسللی يذارک

دضترانؼم فی•

غطتػ بی -ح کترل گ داری -چگگی کبربریيرد ارزیببی در گ يمبدیر –رزا، فتگی ،يبيب

يراحم الذايبتی ک در صرت يبز ب -....داری يثم فػبريالحظبت ایی -تؼير ببیذ اجبو غد يطئل يربع

جت اجبو کبر

دضترانؼم ح کبنيبراضي•

دضترانؼم کترل کيفی داخهی تفطير تبیج•

دضترانؼم ح ارزیببی تبیج ارزیببی خبرجی کيفيت•

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ضمارضگرسللی ضابك •

(در گبو صب در ای) کبنيبراضي-

آيزظ کبربردضتگب -

دضتگب خریذ -

کترل کيفی داخهی الذاو اصالحی-

گ داری ، ضریص بی در ای تؼيرات-

کترل کيفی خبرجی-

-Log book

الذايبت اصالحی پيراي خغب بی دضتگب-

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کىترل کيفی داخلی اضتفبد از خ کترل بب تبریخ امضبی يؼتبر•

رضى چبرت کترنی آگبی کبربر از ح تفطير - تبیج

:اضتفبد از تبز•

T-Britin, Check test ,Duplicate Test, Delta Check , Patient Mean

ضابك يرد ظر•

بررضی بی آيبری-چبرت بی کترنی -

الذايبت اصالحی صرت گرفت -

دلت پبرايتر بی دضتگب -

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Calibration

ب يجػ فؼبنيت بیی اعالق يی غد ک ارتببط •ييب يمبدیر اذاز گيری غذ یک کيت تضظ یک دضتگب یب رظ آزيبیػگبی را بب يمبدیر الؼی آ

يبد ک تضظ رظ بی يرجغ اذاز گيری غذ . اضت يػخص بیذ

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When to Calibrate 1-At installation

2-Complete changes of reagents (i.e., change in type of reagent from same vendor, or

change to a different vendor)

3. When indicated by quality control data

4. After major maintenance or service

5. When recommended by the manufacturer

6. At least every six months

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How • Calibrator

• Fresh blood sample minimum 3 sample each duplicate with reference (manual) and current method

= CF مياوگيه رش دستي - مياوگيه رش دستگاي ×100 •

مياوگيه رش دستگای •

• For best performance, calibrate all the CBC parameters. The WBC differential is calibrated at the factory. They do not require calibration in the laboratory

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Daily startup procedures (Daily Maintenance)

• Daily cleaning

• Background counts

RBC: <0/03 x 1012/l

WBC: <0/04 x 109 / l

Haemoglobin: <0/2g/dl

Platelets: <5 x 109 /l

• Electronic checks

• Run controls

Must be within specified limits

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Manual method

اذاز گيری گهبي اضتفبد از اضتبذارد تبیيذ غذ بب تبریخ امضبی يؼتبر- رلت 4تي يحی اضتبذارد بب حذالم -، ابسار تجيسات کبنيبر Aاضتفبد از ضبیم غيػ ای کالش -

.ضرری يی ببغذ (ييهی نيتر 10الذا در 40) يبکردیهغ - بتکریت

در ضبتریفژ، ػهكرد تبیر،حذاكثر تا فػردگي ضهنب غبرظ گهبل بي ضفيذ پالكت•

اضتفبد از الو ئببر

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رش ای دستی اذاز گيری گهبي

جد دضترانؼم اجبو آزيبیع -

اضتفبد از اضتبذارد تبیيذ غذ بب تبریخ امضبی يؼتبر-

تج ب غرایظ گ داری اضتبذاردب عبك برغر-

رلت 4تي يحی اضتبذارد بب حذالم -

(ييهی نيتر 10الذا در 40) يبکردیهغ -

، ابسار تجيسات Aاضتفبد از ضبیم غيػ ای کالش -- کبنيبر ضرری يی ببغذ

غبرظ گهبل بي ضفيذ پالكت

اضتفبد از الو ئببر-دضترانؼم اجبو آزيبیع

رتيكنضيت –گطترظ خ يحيغي

دضتر انؼم ح کترل کيفی رگ يرد اضتفبد

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رش دستی

بتکریت

دضترانؼم فی دضتگب ييکر بتکریت

دضترانؼم ح کترل کيفی دضتگب

در ضبتریفژ، ػهكرد تبیر،حذاكثر تا فػردگي ضهنب

جدضابك کترل کيفی

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جت اطميىان از دقت صحت کار دستگاي ضمارضگر سللی

چ مستىداتی بايد در آزمايطگاي مجد باضد؟

ضابك گ داری

-فتگی-ضسستط رزاو• ماياو

تعيض محللا•

تعميرات•

ضابك کترل کيفی

چارت کىترلی•

t-Britinرش اماری •

آزمن دتائی•

عدم دقت ماياو•

ضابك کبنيبراضي

پس از تعمير•

با تغيير ضماري سريال • محللا

QCوتايج غيرقابل قبل •

ماي 6حداقل ر •

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فرايىد پس از آزمايص

يكب ،غرایظ گ داري يذت زيب گ داري • بی کهييکی گطترظ خ يحيغی پص از

اجبو آزيبیع

•Critical Value

ح گسارظ فری تبیجی ک در يحذد بحرای .لرار دارذ

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Thank you for your attention