FRCPath Haem Part 1 MCQs-NEQAS UK 479
An external quality assessment (EQA) sample is distributed for a laboratory test. The laboratory's result is compared with the designated target value and the performance is expressed as a Deviation Index (DI).
The laboratory receives the following EQA result:
Deviation Index = +2.6
Which ONE of the following is the most appropriate interpretation?
A. Excellent performance; no action required
B. Good performance; continue routine monitoring
C. Satisfactory performance; no immediate investigation required
D. Borderline performance; investigate possible causes and review trends
E. Poor performance requiring urgent corrective action
Answer: D. Borderline performance; investigate possible causes and review trends
Explanation
The Deviation Index (DI) is a standardised measure of how far a laboratory result deviates from the designated/target value. A positive DI means the laboratory result is higher than the target, while a negative DI means it is lower than the target.
Deviation Index
Interpretation
< −3.0 Requiring investigation
−3.0 to −2.0 Borderline
−2.0 to −1.0 Satisfactory
−1.0 to −0.5 Good
−0.5 to +0.5 Excellent
+0.5 to +1.0 Good
+1.0 to +2.0 Satisfactory
+2.0 to +3.0 Borderline
> +3.0 Requiring investigation
Therefore, a DI of +2.6 indicates a borderline result. The laboratory should review the EQA result in context, including:
Performance in previous and subsequent EQA distributions
Internal quality…