Dr Jim McCullochThistle QA

Johannesburg

Worked in labs from 1965 Experienced and qualified in

Microbiology, Chemistry, Statistics and Clinical Chemistry

Msc Medicine, PhD in Clinical Chemistry Setup Thistle QA in 1990

Started with 1 EQA (PT) in 1990 and with 1 employee, me!

Now... 23 PTs, 12 staff members 2500 labs directly enrolled Data base has results from 60 countries Data base number over 6000

PICK THE CORRECT ANSWER ISO says we need it SANAS will look for it It helps achieve a quality result

To determine the performance of individual labs for specific tests

To monitor the continuing performance of labs

An essential component of a good quality system

Reference values or consensus Defined methods? Outlier detection and removal Statistics to use, robust or not? Size of data base Report issues Customer complaints

Wild results, bummers, etc Chauvenet’s Criterion Grubb’s Test Robust statistics using ISO 13528: 2005, e.g.

iteration

(We) will not be participating in cycle three of what you euphemistically call your quality control scheme.

Quaint statistical manipulation and unacceptable transcription errors render your scheme more than a little suspect.

Please note that we do not require reports. I would sooner the paper be saved for a more useful function than cluttering up my waste paper basket.

Support Teaching material Seminars Extra samples Custom designed reports

They are mere sets of figures, albeit with useful information

They give you warnings, not facts You can be “out of control” and not have

a non-conformance Things are not always what they seem

Myth:Mark Twain said:Lies, damned lies and statistics

Truth:Statistics don’t lie – it’s people who lie!

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04/18/23 Thistle QA 14

By calculation from formulation CRM RM Consensus from reference labs Consensus from participating labs

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Analytes used Sodium, measure of osmotic equilibrium Glucose, likelihood of diabetes Bilirubin, an assessment of liver function

Fitness for purpose – Acceptable Range Sodium 3% Glucose 7.4% Bilirubin 20.0%

Methodology Each lab’s results for an entire 6-month

cycle Reduced to one single figure, CV,

basically, SD as a percentage of the mean / average result

Reviewed for changes per lab, and overall number of labs within the fitness-for-purpose percentage

Findings Sodium 99.9% within f-f-p range Glucose 99.3% within f-f-p Bilirubin 99.1% within f-f-p

General IF first cycle out, next one always in f-f-p UNLESS instrument changes

TSH, thyroid function test, assessment of thyroid stimulation

T4, thyroid function output test PSA, prostate specific antigen

FFP TSH, 20% T4, 15% PSA, 25%

Methodology As for Chemistry

TSH, 94.9% within f-f-p T4, 89.9% within f-f-p PSA, 95% within f-f-p

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PT an essential tool Needs education, interpretation Can assist in complying with quality

standard Detects changes, e.g. Instrument Cannot lead to CQI, rather compliance

with f-f-p