Quality Controlin the

Coagulation Laboratory

BrisbaneAustralia

Robyn Coleman

What is quality control?

An attempt to control and monitor a process to ensure a consistent outcome.

Why perform quality control in a medical laboratory ?

Because we need something to do before the samples arrive

The charts are pretty

Gives the QC officer a reason to come to work

Because the results we produce have a DIRECT effect on the lives of those patients who use our services

Patient• Education• Compliance• Health• Drug

interactions

Dosing Process• DAWN• DR experience

INR

Components for making warfarin therapy safe and effective.

Lab errors measuring PTT’s and INRs linked to bleeding, deaths at hospital.

Reuters Health Information 2003 2003 Reuters Ltd.

Errors in determining prothrombin time began when employees in the lab did not notice that they had been sent an old reagent, and used an incorrect ISI to calculate the INT. Dr Lurie said “they plugged the wrong number into their calculations”

Due to the errors, the lab produced more than 2,000 INR readings that were falsely low. Patients tested during the time of the errors were more likely to experience bleeding complications. Three patient deaths were attributable to the mistake.

The Sample Collection technique Contamination by heparin or saline flushes Ratio of blood to anticoagulant (9:1) Low HCT causes change in final citrate

concentration Adequate mixing of sample without frothing Transportation to testing facility

- delay in testing Clotted, haemolysed, icteric or lipaemic

specimen Incorrectly or unlabelled sample

Sources of error in the coagulation lab.

Change in INR vs Storage Time

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Change in INR vs storage time

Storage time (days) 40C

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Reagent related problems Selection of an appropriate reagent

Contaminated reagents

Reconstitution with incorrect volumes

Reconstitution with incorrect diluent

Defects in product due to mishandling in shipping and storage

Reagent used beyond stated stability or expiration date

Contaminated water used for reconstitution

Analytical Errors

Incorrect value assignment

( ISI , MNPT or std value)

Incorrect incubation or activation time

Incorrect or imprecise dispensing of reagents

Failure to use proper instrument operating procedures

Extrapolation beyond readable limits of reference curve

Failure to action instrument warning flags

Instrument Failure Defective light source or detection system

Incorrect temperature

Poor reagent / sample delivery

Electrical Interferences

Reagent splash

Mechanical failure, e.g. reagent stirring etc

The most common source of error

Human error !

Internal –

Daily Verify I, II, III for PT, INR, APTT, Fib

Should be run minimum daily or every 8 hours or every 40 samples or with new bottle of reagent

Patient samples should not be tested until QC accepted

If fails , retest by elimination until fault found

External –

Monthly central review of Mean, SD of daily review

RCPA (and central review of)

Quality control

2003COAG Veri fy Monthly QC Jul-03

INR=F0000 Veri fy 1FIB=F1080

PT INR APTT FIBLab Mean SD Mean Mean SD Mean SD V1 V2 V3 Th/plas t in Platelin LS

ACL BSA 13.38 0.24 0.97 28.57 0.35 2.44 0.10 161675 161728 161688 1220205 111091PT=F0015 BUN 13.04 0.22 0.99 28.35 0.38 2.84 0.13 161672 161679 161688 1220205 111091APTT=0200 COF 12.89 0.16 0.95 28.45 0.77 3.15 0.20 161672 161728 161688 1220205 111091

GPH1GPH2GRF 13.17 0.30 0.99 27.63 0.83 2.98 0.20 161672 161679 161688 N1220205 111091HER 13.34 0.22 1.01 28.30 0.51 2.56 0.23 161675 161728 161688 1220205 111091MAR 13.26 0.31 1.03 28.70 0.65 2.76 0.21 161675 161728 161688 1220205 111091MPR 13.46 0.30 1.02 28.48 1.12 2.93 0.17MYB 13.42 0.22 1.00 29.17 0.30 2.95 0.14 161675 161728 161688 1220205 111091TSV 13.00 0.50 0.98 28.50 1.11 3.06 0.25 161675 161728 161688 1220205 111091Mean 13.2 1.00 28.5 0.6 2.8 0.2SD 0.2 0.4 0.2

CA540 CAIPT=0020 GPHAPTT=0200 LIS 10.68 0.33 1.01 27.75 0.64 2.52 0.69 161675 161728 161688 828542 111091

SPT 12.90 9.00 1.10 31.52 12.75 2.86 0.32 161675 161728 161688 828542 111091TPL 14.80 1.10 1.00 27.40 0.50 2.90 0.30 161672 161679 161625 828542 111091TSA 10.70 0.40 1.00 27.00 55.10 3.19 0.22 161675 161728 161658 828542 111091TUGW ES

CA1000 TPL 16.00 2.60 1.02 29.80 1.20 3.35 0.20 161672 161679 161625 828542 111091CA6000 ROC 10.30 0.40 1.00 30.60 0.80 3.19 0.10 161672 161728 161688 828542 111091

Mean 13.02 2.69 1.03 28.69 14.04 2.96 0.35SD 2.41 0.04 1.88 0.30

STA Taringa 11.90 0.16 1.00 30.10 0.67 3.58 0.15 161672 161728 161688 828542 111091STAR Taringa 12.20 0.23 1.00 XX XX XX XX 161672 161728 161688 828542 111091

Manual GLA 12.07 0.47 1 34.45 1.69 161675 161728 161688 828542 111091

Feb 03 Verify QC-INR

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Verif y I

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RCPA

Royal College of Pathologists

Haematology QAP- Haemostasis POC care – INR module INR, APTT, Fibrinogen and D-Dimer Special Haemostasis

Thrombophilia

von Willebrand testing

NATA

National Accreditation and Testing Authority Primary function is Proficiency testing Peer review of all technical processes Licence to provide pathology services Regular review every 3 years Corporate surveillance

NATA Assessment

Relevant documentation( including its currency) Appropriateness of methods and procedures Suitability of equipment or instruments ( incl calibration ) Suitability of environment and supporting services Adequacy of personnel ( number, training, skills etc) Monitoring of processes / quality control measures Handling and identification of test specimens or test items Recording and reporting of results –documentation control

ISO9001/ IEC 17025

Traceability and accountability Quality systems ( Documentation) Non conformance

Complaints ( Internal and External) Classification and review of NCie Why did this error occur ? Random or system error Corrective or preventative actions

Audits – allows regular review of all processes. Horizontal Vertical

So the aim for laboratory staff…

Produce consistent results,consistently

Pay attention to what is happening

(eg new lot numbers)

Don’t assume it will be alright eventually.

Don’t assume it is someone else’s responsibility.

Trace ability and accountability.

Action faults efficiently and effectively.

Pro actively prevent faults by doing instrument maintenance