TABLE 3.
Sensitivity and specificity of various TB testing algorithms
| Test-positive, culture-positive n | Test-positive, culture-negative n | Test-negative, culture-positive n | Test-negative, culture-negative n | Sensitivity | Specificity | PPV | NPV | |
|---|---|---|---|---|---|---|---|---|
| SOC Arm* | 44 | 14 | 42 | 422 | 51.2 (40.8–61.4) | 96.8 (94.7–98.1) | 75.9 (63.5–85.0) | 90.9 (88.0–93.2) |
| Xpert Arm† | 49 | 25 | 21 | 362 | 70.0 (58.5–79.5) | 93.5 (90.6–95.6) | 66.2 (54.9–76.0) | 94.5 (91.8–96.4) |
| Xpert alone | 41 | 4 | 27 | 381 | 60.3 (48.4–71.1) | 99.0 (97.4–99.6) | 91.1 (79.3–96.4) | 93.4 (90.5–95.4) |
| Xpert in smear-negative | 25 | 4 | 24 | 381 | 50.0 (36.6–63.4) | 99.0 (97.4–99.6) | 86.2 (69.4–94.5) | 93.9 (91.1–95.8) |
| Xpert in smear-positive | 13 | 0 | 3 | 0 | 81.3 (57.0–93.4) | — | 100.0 (77.2–100.0) | 0.0 (0–56.1) |
* Any positive result on smear and/or history and physical examination and/or CXR that resulted in the initiation of anti-TB treatment.
† Any positive result on Xpert and/or smear and/or history and physical examination and/or CXR that resulted in the initiation of anti-TB treatment.
SOC = standard of care; PPV = positive predictive value; NPV = negative predictive value; CXR = chest X-ray.