Table 2 Fluorescence smear microscopy, GeneXpert MTB MTB/RIF® and Loopamp MTBC Detection Kit® performance
Diagnosis assay | TP | TN | FP | FN | Sensitivity | Specificity | PPV | NPV |
|---|---|---|---|---|---|---|---|---|
n | n | n | n | % (95% CI) | % (95% CI) | % (95% CI) | % (95% CI) | |
Fluorescence smear microscopy | ||||||||
Total (n = 514) | 148 | 310 | 3 | 53 | 73.6 (67.1–79.3) | 99.0 (97.1–99.8) | 98.0 (94.1–99.6) | 85.4 (81.4–88.7) |
GeneXpert MTB/RIF® | ||||||||
Smear negative (n = 361) | 29 | 300 | 8 | 24 | 54.7 (41.4–67.4) | 97.4 (94.9–98.8) | 78.4 (62.6–88.9) | 92.6 (89.2–95.0) |
Smear positive (n = 148) | 145 | 0 | 0 | 3 | 98.0 (93.9–99.6) | N/A | 100.0 (96.9–100.0) | N/A |
Total (n = 509) | 174 | 300 | 8 | 27 | 86.6 (81.1–90.7) | 97.4 (94.9–98.8) | 95.6 (91.4–97.9) | 91.7 (88.2–94.3) |
Loopamp MTBC Detection Kit® | ||||||||
Smear negative (n = 369) | 29 | 311 | 5 | 24 | 54.7 (41.4–67.4) | 98.4 (96.2–99.4) | 85.3 (69.4–94.0) | 92.8 (89.5–95.2) |
Smear positive (n = 148) | 141 | 0 | 0 | 7 | 95.3 (90.4–97.9) | N/A | 100.0 (96.8–100.0) | N/A |
Total (n = 517) | 170 | 311 | 5 | 31 | 84.6 (78.9–89.0) | 98.4 (96.2–99.4) | 97.1 (93.3–99.0) | 90.9 (87.4–93.6) |