Tuberculosis Research and Treatment / 2015 / Article / Tab 3 / Research Article
Comparison of Xpert MTB/RIF Assay and the Conventional Sputum Microscopy in Detecting Mycobacterium tuberculosis in Northern Thailand Table 3 Sensitivity, specificity, positive predictive value, and negative predictive value of Xpert assay and sputum acid-fast smear comparing to sputum culture.
Xpert assay 95% confidence interval Acid-fast smear 95% confidence interval Specimens from all patients ( ) SEN 41/43 = 95.3% 84.2–99.4% 26/43 = 60.5% 44.4–75.0% SPEC 57/66 = 86.4% 75.7–93.6% 65/66 = 98.5% 91.8–100% PPV 41/50 = 82.0% 68.6–91.4% 26/27 = 96.3% 81.0–99.9% NPV 57/59 = 96.6% 88.3–99.6% 65/82 = 79.3% 68.9–87.4% Specimens from HIV-infected patients ( ) SEN 10/10 = 100% 69.2–100% 6/10 = 60% 26.2–87.8% SPEC 16/16 = 100% 79.4–100% 19/19 = 100% 82.4–100% PPV 10/13 = 76.9% 46.2–95.0% 6/6 = 100% 54.1–100% NPV 16/16 = 100% 79.4–100% 19/23 = 80% 61.2–95.0% Specimens from HIV-uninfected patients ( ) SEN 28/30 = 93.3% 77.9–99.2% 20/30 = 66.7% 47.2–82.7% SPEC 41/43 = 95.3% 84.2–99.4% 46/47 = 97.9% 88.7–99.9% PPV 28/34 = 82.4% 65.5–93.2% 20/21 = 95.2% 76.2–99.9% NPV 41/43 = 95.3% 84.2–99.4% 46/56 = 82.1% 69.6–91.1%
SEN: sensitivity; SPEC: specificity; PPV: positive predictive value; NPV: negative predictive value.