Table 2. Diagnostic performance of Xpert Ultra and smear using culture as the reference standard.
| Method | Pulmonary samples (n = 1120) | Extra-pulmonary samples (n = 461) | ||||||
|---|---|---|---|---|---|---|---|---|
| Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | |
| (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | (95% CI) | |
| Smear | 53,4 | 99,1 | 87,5 | 94,8 | 22,5 | 99,3 | 75 | 93,1 |
| (44–62,6) | (98,3–99,6) | (77,6–94,1) | (93,2–96) | (10,8–38,5) | (97,9–99,9) | (42,8–94,5) | (90,3–95,3) | |
| Xpert Ultra assay (all samples) | 91,5 | 95,5 | 70,6 | 99 | 90 | 91,9 | 51,4 | 99 |
| (85–95,9) | (94–96,7) | (62,7–77,7) | (98,1–99,5) | (76,3–97,2) | (88,9–94,3) | (39,1–63,6) | (97,4–99,7) | |
| Smear positive | 100 | 88,9 | 98,4 | 100 | 100 | 66,7 | 90 | 100 |
| (94,3–100) | (51,8–99,7) | (91,6–100) | (63,1–100) | (66,4–100) | (9,4–99,2) | (55,5–99,8) | (15,8–100) | |
| Smear negative | 81,8 | 95,6 | 50,6 | 99 | 87,1 | 92,1 | 45 | 99 |
| (69,1–90,9) | (94,1–96,8) | (39,8–61,3) | (98,1–99,5) | (70,2–96,4) | (89,1–94,5) | (32,1–58,4) | (97,4–99,7) | |
PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval.