The sensitivity of a screening test for cervical cancer is 80% and specificity is 90%. In a population of 1000 women where the prevalence of cervical cancer is 10%, the Positive Predictive Value (PPV) is:
- A 62%
- B 80%
- C 47% ✓
- D 90%
Correct answer: C. 47%
Explanation
True positives (TP) = 100 × 0.80 = 80; false positives (FP) = 900 × 0.10 = 90. PPV = TP/(TP+FP) = 80/(80+90) = 80/170 ≈ 47%. The 10% prevalence means only 100 truly diseased individuals, and the relatively high false-positive rate (90 FP) substantially lowers PPV even with good specificity. Options B, C and D overestimate PPV.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.