Best of five
- A. Spectrum bias from testing populations with different disease severity and prevalence
- B. Randomisation failure in every diagnostic study
- C. Publication bias alone
- D. Lead-time bias
- E. Recall bias
FRCS (ORL-HNS) · SECTION 1 SBA
Diagnostic test spectrum bias
A new neck-mass test performs well in a tertiary cancer clinic but poorly in primary care. What best explains the discrepancy?
A. Spectrum bias from testing populations with different disease severity and prevalence
Diagnostic accuracy can change when the evaluated case mix differs from real-world users. A tertiary cohort with advanced disease may overestimate sensitivity and alter predictive values.
Why every option is right or wrong
A. Spectrum bias from testing populations with different disease severity and prevalence: Diagnostic accuracy can change when the evaluated case mix differs from real-world users. A tertiary cohort with advanced disease may overestimate sensitivity and alter predictive values.
B. Randomisation failure in every diagnostic study: Randomisation is not required to explain this case-mix effect.
C. Publication bias alone: Selective publication may distort evidence but does not specifically describe population-spectrum differences.
D. Lead-time bias: This affects apparent survival after earlier diagnosis.
E. Recall bias: This concerns inaccurate retrospective exposure reporting.
What if the scenario changed?
If sensitivity and specificity were stable but positive predictive value fell in primary care, lower disease prevalence would be the principal explanation.
Independent Clinora educational preparation material; not official JCIE content, an accredited programme, clinical advice, or a substitute for current guidance, local policy and specialist judgement.
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