VITAL DX v4.0 • VERIFIED QUANTITATIVE BRIEFING
Bayesian Positive Predictive Value: 90% Sens / 80% Spec / 10% Prevalence
With 90% sensitivity, 80% specificity, and 10% disease prevalence, the Positive Predictive Value (PPV) of a positive test is 33.3%.
Bayes Theorem: PPV = TP / (TP + FP) = (90% × 10%) / [(90% × 10%) + (20% × 90%)] = 33.3%.
FAQ: What is the PPV when sensitivity is 90%, specificity is 80%, and prevalence is 10%?
The Positive Predictive Value (PPV) is 33.3%, meaning 66.7% of positive results at 10% prevalence are false positives.