VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 84% Sens / 84% Spec / 2% Prevalence
With 84% sensitivity, 84% specificity, and 2% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 9.7%.
Bayes Theorem: PPV = TP / (TP + FP) = (84% × 2%) / [(84% × 2%) + (16% × 98%)] = 9.7%.
FAQ: What is the PPV when sensitivity is 84%, specificity is 84%, and prevalence is 2%?
The Positive Predictive Value (PPV) is 9.7%, meaning 90.3% of positive results at 2% prevalence are false positives.