VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 80% Sens / 98% Spec / 2% Prevalence
With 80% sensitivity, 98% specificity, and 2% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 44.9%.
Bayes Theorem: PPV = TP / (TP + FP) = (80% × 2%) / [(80% × 2%) + (2% × 98%)] = 44.9%.
FAQ: What is the PPV when sensitivity is 80%, specificity is 98%, and prevalence is 2%?
The Positive Predictive Value (PPV) is 44.9%, meaning 55.1% of positive results at 2% prevalence are false positives.