TABLE 2.
Xpert assay performance
| Specimen category and typea | No. of specimens tested | No. (%) of specimens classified as: |
No. of specimens with definitive results confirmed by reference culture | % Xpert sensitivity (95% CI) | % Xpert specificity (95% CI) | |||||
|---|---|---|---|---|---|---|---|---|---|---|
|
M. tuberculosis positive |
M. tuberculosis negative |
Contaminated/error |
||||||||
| MGIT culture | Xpert | MGIT culture | Xpert | MGIT culture | Xpert | |||||
| All | 1,175 | 277 (23.5) | 260 (22) | 774 (65.9) | 909 (77.4) | 124 (10.5) | 6 (0.5) | 1,045 | 59 (53–65) | 92 (90–94) |
| Pus | 119 | 43 (36) | 62 (52) | 49 (41) | 62 (52) | 27 (23) | 92 | 91 (78–97) | 76 (60–85) | |
| Aspirate | 84 | 20 (23.8) | 30 (46) | 55 (65.5) | 54 (64) | 9 (10.7) | 75 | 80 (56–94) | 78 (65, 88) | |
| Fluid | 890 | 206 (23) | 159 (18.3) | 612 (69) | 725 (81) | 72 (8) | 6 (0.7) | 812 | 51 (44–58) | 94 (92, 96) |
| Other | ||||||||||
| CSF | 37 | 4 (11) | 3 (8) | 32 (87) | 34 (92) | 1 (3) | ||||
| Tissue biopsy | 31 | 3 (10) | 5 (16) | 19 (61) | 26 (84) | 9 (29) | ||||
| Urine | 10 | 1 | 4 | 10 | 5 | |||||
| Bone | 4 | 1 | 3 | 3 | 1 | |||||
| Fluids | ||||||||||
| Plueral | 528 | 482 | 47 (38–56) | 94 (91–96) | ||||||
| Ascitic | 153 | 139 | 59 (41–76) | 97 (92–99) | ||||||
| Other | 209 | 191 | 54 (39–69) | 92 (87–96) | ||||||
a
Fluids considered as a group and fluid types examined individually reflect data from the same specimens.