VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 98% Sens / 86% Spec / 2% Prevalence
With 98% sensitivity, 86% specificity, and 2% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 12.5%.
Bayes Theorem: PPV = TP / (TP + FP) = (98% × 2%) / [(98% × 2%) + (14% × 98%)] = 12.5%.
FAQ: What is the PPV when sensitivity is 98%, specificity is 86%, and prevalence is 2%?
The Positive Predictive Value (PPV) is 12.5%, meaning 87.5% of positive results at 2% prevalence are false positives.