Figure 1

Performance of a Diagnostic Tool with Sensitivity & Specificity of 95%. A diagnostic tool with a high sensitivity and specificity results in a substantial proportion of false positives (among individuals with a positive test) when the prevalence of diseased individuals in the screening population is low; as the prevalence increases, the proportion of false positives decreases. *Proportion of False Positives: Proportion of individuals with a positive test who do not have the disease = (number of false positives)/(number of true positives + number of false positives).