Figure 1From: PCR colorimetric dot-blot assay and clinical pretest probability for diagnosis of Pulmonary Tuberculosis in Smear-Negative patients Simulation of positive and negative predictive values of ZN and Culture/PCR dot-blot tests, according to different TB prevalence rates. PPV: Positive Predictive Value, NPV: Negative Predictive Value, PP: pretest probability (clinical suspicion); TB prevalence rates: from 5% to 48.8%Back to article page