Factors InfluencingQuality lecture 1

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Problem Scenario

You want to have an overall view of what can influence the quality of your results concerning a new PCR test on H5N1 which has been set up in your laboratory. Establish the checklist you will use.

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The Quality System

Process Control

(Quality Control & Specimen

Management)

Purchasing & Inventory

AssessmentOccurrence

Management

Information Management

Process Improvement

Customer Service

Facilities & Safety

Organization Personnel Equipment

Documents & Records

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Learning Objectives

At the end of this activity, you will be able to: Understand the main factors influencing quality

of analysis results Understand the importance of ALL the different

factors in the production of reliable results

1. Examples of factors influencing quality

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An Example: HIV

Factors influencing quality: Bad/inadequate sample identification Contamination (cross-sample contamination, distillated

water quality, contaminated micropipettes, reuse of ELISA plates)

Bad incubation of ELISA plates (if needed) Bad equipment (bad wavelength, etc.) Bad reagents (expired, bad conservation temperature, low

sensibility, inadequacy, etc.) No or bad quality control (internal/external)

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An Example: HIV (continued)

Factors influencing quality: Destruction of the plate’s coating with the micropipette Misuse of the micropipette (bad tips, bad calibration) Irregularity of the measurements due to the lack of written

techniques Result transcription mistakes Result back mistakes (telephone especially) False positive, false negative

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Another Example

Data from JAMA, 1996 Survey done in the USA Frequency of laboratory mistakes: 1 %o

7 % in the analytical step 93 % in pre/post analytical steps

45 % of the mistakes are important, with consequences for diagnosis and/or treatment of the disease

Most common mistakes = copying/recopying mistakes

2. The common mistakes

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How is quality affected?

The common mistakes: Analysis prescription Sampling conditions Specimen transport and conservation Training level of technical staff Reagents and equipment quality Insufficiency of control procedures Analytical process Interpretation of raw results Transcription and diffusion of the results Interpretation and use of the results

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Analysis Prescription Bad prescription

Too much: toxoplasmosis IgM for prenatal checking Not enough: IgG only during acute phase of a disease,

pathogen micro-organism without AST, Pneumococcus without penicillin MIC…

Inadequate: normal urine analysis for urethritis, bacteriological analysis after treatment initiation

Incomplete prescription Suspicion of typhoid fever, stool culture without blood

culture or vice versa No verification of the efficiency of some treatments (stool

parasites) Anarchical self-prescription (low)

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Sampling Conditions Bad identification of the specimen, incomplete or

unreadable identification Inadequate sampling material (contaminated, containing

disinfectants, multiple use, bad anticoagulant) Inadequate timing of samples:

Sampling after ATB treatment begins Cyclic sampling (filariosis, cortisol) not respected Sampling outside fever acme (malaria, septicemia) or if

hypothermia or if acute phase of the disease (typhoid fever: blood culture before W4)

Long tourniquet time for coagulation tests Inadequate sample: first drop of urine for standard urine

analysis (considered as urethral sample)

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Specimen Transport & Conservation

Inadequate conservation delay Inadequate transportation and conservation temperature Blood sample badly prepared (slow centrifugation, RBC not

separated, frozen without separating RBC) None or inappropriate transport media (Cary-Blair media for

meningitis) Packaging conditions (biosafety regulations, compatibility

with further analysis, addressee contact information) Addressee absent or not reachable No follow-up of the specimen by the sender

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Training Level of Technical Staff Insufficient training level:

Sampling Biosafety Technical Analysis management (logbooks, data, reports, conclusions)

Large inter-technician variability (between technicians) Large intra-technician variability (in one technician) Lack of continuous training and refreshing Techniques not standardized, not unified in the country

large variability between laboratories Lack of training for support staff (cleaners, janitors, reagents

preparation, etc.) Inadequation between initial training and current

responsibilities

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Reagents and Equipment Quality

Usually “least expensive” often “worst quality” No/little preventive maintenance No/little meticulous follow-up of the cold chain and how

equipment are functioning No duplication of critical equipment, no possibility to refer

the specimen if there are analysis problems No expiration logbook, use of expired or badly conserved

reagents No check of spectrophotometers and ELISA readers

(parasitic light, absorbance, band-width, linearity, etc.) No periodical calibration of the equipment

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Analytical Process

Lack of written technique or containing lots of deletions and changes

Old or imprecise technique (Stokes techniques for AST, Kovacs on urine, AST on pure urine, etc.)

Analysis of the inadequate part of the specimen (sputum for TB, bloody diarrhoea)

Serum pooling! Petri dishes split in two (or even in four), reuse of micropipette tips

Insufficient time devoted to the analysis (20 minutes minimum for malaria and TB)

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Insufficiency of Control Procedures No quality assurance system No quality supervisor in the laboratory No national list of registered reagents (or no official

use of the list of another country) No control of culture media, no logbook for the

preparation of media and reagents No positive and negative control for serologies and

other analyses No standardisation of inoculums for AST No participation in any EQC programme

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Interpretation of Raw Results Total dissociation of the units (chemistry, haematology,

bacteriology) problem for global validation No interpretation of bacterial resistances (no expert system) Special physiological situations not integrated:

Children/Pregnant women/The elderly Special pathological situations not integrated:

Renal/liver insufficiency Dehydration/High temperature

No access to patient history Lack of critical thinking concerning results Too much confidence in the automated analyzer

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Transcription and Diffusion of Results

Reminder: the signing biologist might also be in charge of results transmission

Results transcription mistakes; most common mistake in a laboratory

“Rapid” validation/signature unable to avoid incoherence

Delays in result transmission Insufficient, incomplete or delayed weekly report to

surveillance services

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Interpretation and Use of Results

No conclusion or comments on the analysis report Bad interpretation by the prescriber/clinician Prescribers lack confidence in laboratory results

(Communication? Quality assurance? Other?) No access to patient history Incorrect use of the data by surveillance services:

Data integration Denominator problems

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Controllable factors or not? 2 different types of factors:

Controllable by the laboratory (usually analytical factors)

Non controllable by the laboratory (pre and post analytical factors in general)

Final goal: Decrease factors controllable by the lab Communicate with pre and post analytical actors

in order to help them control these factors

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Don’t forget

Stock managt

IQC, EQCQAM

Equipment & maintenance

Analysis and reports

management

Analysis

PrescriptionInterpretation

Cold chain

Training level of the staff

Reagents and consumables

Organization

Sampling

Summary

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Summary

Each of the twelve Quality System essentials can be influenced by many factors

This Set of coordinated activities must function as building blocks for quality management.

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Problem Scenario

You want to have an overall view of what can influence the quality of your results concerning a new PCR test on H5N1 which has been set up in your laboratory. Establish the checklist you will use.