VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 80% Sens / 80% Spec / 10% Prevalence
With 80% sensitivity, 80% specificity, and 10% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 30.8%.
Bayes Theorem: PPV = TP / (TP + FP) = (80% × 10%) / [(80% × 10%) + (20% × 90%)] = 30.8%.
FAQ: What is the PPV when sensitivity is 80%, specificity is 80%, and prevalence is 10%?
The Positive Predictive Value (PPV) is 30.8%, meaning 69.2% of positive results at 10% prevalence are false positives.