Biostatistics & Study Design USMLE Step 1 Practice Question
A 34-year-old woman with fever (38.9°C), cough, and myalgias presents to the emergency department in July. Rapid influenza assay is positive. Chest X-ray shows no infiltrates. She denies recent travel or sick contacts. The same influenza test used during winter peak season (15% prevalence) maintains identical sensitivity (95%) and specificity (98%) year-round. During summer months when influenza prevalence drops to 0.5%, which parameter is most likely to increase?
Answer choices
- ASensitivity
- BSpecificity
- CPositive predictive value
- DFalse-positive rate
- ENegative predictive valueCorrect answer
- FFalse-negative rate
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