A screening test for cervical cancer is applied to 500 women with confirmed disease and 500 without disease. The test is positive in 450 women with disease and 50 without disease. The Positive Predictive Value (PPV) at this prevalence of 50% is:

• A 82%
• B 89%
• C 95%
• D 90% ✓

Explanation

TP = 450, FP = 50, FN = 50, TN = 450. PPV = TP / (TP + FP) = 450 / (450 + 50) = 450/500 = 0.90 = 90%. Sensitivity = 450/500 = 90% and Specificity = 450/500 = 90%. At 50% prevalence, PPV = Sensitivity in this symmetric scenario, yielding 90%.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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