Table 4.
Accuracy indices for LPA
| Reference test | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | +LR | −LR |
|---|---|---|---|---|---|---|
| Culture (n = 80) | 81.5 (67.4–91.1) | 87.5 (71–96.5) | 90.7 (77.9–97.4) | 75.7 (58.8–88.2) | 6.5 (2.57–16.4) | 0.214 (0.12–0.4) |
| Xpert (MTB/Rif) (n = 89) | 80 (68.2–88.9) | 100 (85.8–100) | 100 (93.2–100) | 64.9 (47.5–79.8) | 0.2 (0.12–0.33) | |
| Culture for rifampicin resistance (n = 48) | 100 (85.2–100) | 93.8 (69.8–99.8) | 95.8 (78.9–9.9) | 100 (78.2–100) | 16 (2.4–107) | 0 |
| Xpert (MTB/Rif) for rifampicin resistance (n = 65) | 94.3 (80.8–99.3) | 94.1 (71.3–99.9) | 97.1 (84.7–99.9) | 88.9 (65.3–98.6) | 16 (2.39–108) | 0.061 (0–0.23) |
| Culture for isoniazid resistance (n = 48) | 89.3 (71.8–97.7) | 100 (71.5–100) | 100 (86.3–100) | 78.6 (49.2–95.3) | 0.107 (0.37–0.31) | |
| Culture (smear positive samples) (n = 51) | 82.2 (67.9–92) | 66.7 (22.3–95.7) | 94.9 (82.7–99.4) | 33.3% (9.9–65.1) | 2.47 (.79−7.7) | .267 (.11–.62) |
| Xpert MTB/Rif (smear positive samples) (n = 60) | 80.3 (68.2–89.4) | 100 (2.5–100) | 100% (92.7–100) | 7.69% (.2– 36) | .20 (.12–.33) | |
| Culture (smear negative samples) (n = 29) | 66.7% (9.4–99.2) | 92.3 (74.9–9.1) | 50 (6.76–93.2) | 96 (79.6–99.9) | 8.67 (1.8−41) | .361 (.073−1.8) |
| Xpert MTB/Rif (smear negative samples) (n = 29) | 66.7 (22.3–95.7) | 100 (85.2–100) | 100 (39.8–100) | 92 (74–99) | .333 (.11–1.0) |
Notes: Data in parentheses are 95% CI, unless otherwise indicated; PPV – positive predictive value, NPV – negative predictive value, +LR – positive likelihood ratio, −LR – negative likelihood ratio.