Today, as part of World Quality Week, our laboratory team held a training session on reviewing External Quality Assessment (EQA) performance. The question at the centre of it was simple: once an EQA result arrives, what do we do with it?
What is EQA?
External Quality Assessment, also called proficiency testing, is how a laboratory checks itself against others. An independent provider sends samples whose answers the laboratory doesn’t know. The laboratory tests them exactly as it tests patient samples, with the same staff, machines and procedures, and sends its results back.
The provider compares each laboratory’s answer with the correct value, or with the average of laboratories using the same method, and returns a score.
Why a score on its own isn’t enough
A pass is reassuring. It doesn’t make a patient safer by itself, though. What protects patients is what the laboratory does with the result.
Many schemes report a z-score, which shows how far a result sits from the target. As a general guide:
- within 2 is satisfactory
- between 2 and 3 is questionable and worth a closer look
- 3 or more is unsatisfactory and must be investigated
Scoring rules differ between schemes, so a review always starts from the provider’s own report.
What a review looks at
- Every unsatisfactory result. Each one is investigated until the cause is found.
- Results that only just passed. A borderline score can be the first warning of a problem.
- Trends across several rounds. Results drifting in one direction can point to a calibration or reagent problem long before anything fails.
- Simple slips. Some failures come from a typing error or the wrong units when the result was submitted. They still count, because the same slip could happen on a patient’s report.
From a finding to a fix
When a review finds a problem, the team traces it back through the whole process: how the sample was received and stored, the reagents and their batch numbers, calibration, the machine’s maintenance record, and how the result was calculated and reported.
Then comes the corrective action, a check that it worked, and a written record. If there’s any chance patient results from the same period were affected, those are reviewed too.
Why it matters for ISO 15189
ISO 15189:2022, the international standard for medical laboratories, requires an accredited laboratory to take part in EQA, review its performance and act on what it finds. Assessors check this record at every audit. Link Medical Diagnostic and Research Laboratories is accredited to ISO 15189:2022, so this review is part of how we work all year, not just during Quality Week.
What it means for you
You won’t ever see an EQA report, but it stands behind every result we issue. When your doctor reads your result, they need to trust that the same sample would give the same answer in any good laboratory. EQA is one of the ways we check that it would.
Book a test
Link Medical Diagnostic and Research Laboratories is at 19 Sam Mbakwe Avenue, World Bank Road, Owerri, beside Haven Suites Hotel. We’re open 8am to 5pm, Monday to Saturday. Call or WhatsApp 0908 195 1300, or book a lab visit online. If you can’t come in, ask about home sample collection.
This article is general information and doesn’t replace advice from your doctor. Take your results to a qualified healthcare professional for interpretation.
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