A new screening test for cervical cancer using HR-HPV DNA testing has 92% sensitivity and 88% specificity. In a population where cervical cancer prevalence is 2%, the Positive Predictive Value (PPV) is approximately:
- A 13.6% ✓
- B 40.2%
- C 88%
- D 92%
Correct answer: A. 13.6%
Explanation
PPV = TP/(TP + FP). Using 10,000 population: True positives = 200 × 0.92 = 184; False positives = 9800 × 0.12 = 1176; PPV = 184/(184+1176) = 184/1360 ≈ 13.5%. This illustrates that even a high-performance test has low PPV in low-prevalence populations, generating many false positives and leading to unnecessary colposcopies. Sensitivity and specificity are properties of the test; PPV and NPV depend on prevalence — a critical concept in screening programme design.
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.