Table 3 Clinical performance and programmatic impact of three diagnosis algorithms
Algorithm | TP | TN | FP | FN | Sensitivity | Specificity | PPV | NPV | Molecular testing | Additional case notification | Total case notification | LR+ | LR- |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
n | n | n | n | % (95% CI) | % (95% CI) | % (95% CI) | % (95% CI) | n (%) | n | n | |||
Algorithm 1 | |||||||||||||
Smear (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) | 0 (0) | N/A | 151 | 76.8 | 0.3 |
Algorithm 2 | |||||||||||||
GeneXpert MTB/RIF® (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) | 509 (100.0) | 31 | 182 | 33.3 | 0.1 |
Loopamp MTBC Detection Kit® (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) | 517 (100.0) | 24 | 175 | 53.5 | 0.2 |
Algorithm 3 | |||||||||||||
Smear - followed by GeneXpert MTB/RIF® (n = 506) | 177 | 295 | 10 | 24 | 88.1 (82.8–91.9) | 96.7 (94.0–98.3) | 94.7 (90.3–97.2) | 92.5 (89.0–94.9) | 358 (70.1) | 36 | 187 | 26.9 | 0.1 |
Smear - followed by Loopamp MTBC Detection Kit® (n = 514) | 177 | 307 | 6 | 24 | 88.1 (82.8–91.9) | 97.5 (95.0–98.8) | 96.7 (92.9–98.7) | 92.8 (89.4–95.1) | 366 (71.2) | 32 | 183 | 45.9 | 0.1 |