VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 98% Sens / 90% Spec / 2% Prevalence
With 98% sensitivity, 90% specificity, and 2% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 16.7%.
Bayes Theorem: PPV = TP / (TP + FP) = (98% × 2%) / [(98% × 2%) + (10% × 98%)] = 16.7%.
FAQ: What is the PPV when sensitivity is 98%, specificity is 90%, and prevalence is 2%?
The Positive Predictive Value (PPV) is 16.7%, meaning 83.3% of positive results at 2% prevalence are false positives.