VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 90% Sens / 98% Spec / 2% Prevalence
With 90% sensitivity, 98% specificity, and 2% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 47.9%.
Bayes Theorem: PPV = TP / (TP + FP) = (90% × 2%) / [(90% × 2%) + (2% × 98%)] = 47.9%.
FAQ: What is the PPV when sensitivity is 90%, specificity is 98%, and prevalence is 2%?
The Positive Predictive Value (PPV) is 47.9%, meaning 52.1% of positive results at 2% prevalence are false positives.