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Spectrum bias — USMLE Step 3 MCQ

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HardPreventive Medicine, Epidemiology, BiostatisticsSpectrum biasUSMLE Step 3

A new rapid strep test performs well in a study of hospitalized children with severe pharyngitis and healthy controls. In primary care, sensitivity is lower among children with milder symptoms and overlapping viral features. Which of the following is the most likely diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Spectrum bias

Spectrum bias occurs when test performance differs because the validation population does not match the clinical population in disease severity or case mix.

Reference: USMLE Step 3 biostatistics and population health content outline: https://www.usmle.org/exam-resources/step-3-materials/step-3-content-outline-and-specifications