Table 2.
Performance of specimens tested by Xpert relative to culture in children
| Sensitivity | Specificity | |||||||
|---|---|---|---|---|---|---|---|---|
| Specimen type | Positive | MGIT Pos |
% | (95% CI) | Negative | N** | % | (95% CI) |
| One specimena | ||||||||
| Gastric aspirate | 13 | 21 | 61.9 | (40.9 - 79.2) | 251 | 252 | 99.6 | (97.8 - 99.9) |
| String | 6 | 10 | 60 | (31.3 - 83.2) | 258 | 260 | 99.2 | (97.2 - 99.8) |
| Induced sputum | 8 | 12 | 66.7 | (39.1 - 86.2) | 256 | 257 | 99.6 | (97.8 - 99.9) |
| Nasopharyngeal aspirate | 13 | 21 | 61.9 | (40.9 - 79.2) | 245 | 246 | 99.6 | (97.7 - 99.9) |
| Stool | 6 | 7 | 85.7 | (48.7 - 97.4) | 230 | 236 | 97.5 | (94.6 - 98.8) |
| Urine | 2 | 2 | 100 | (34.2 - 100.0) | 231 | 233 | 99.1 | (96.9 - 99.8) |
| FNAB | 2 | 3 | 66.7 | (20.8 - 93.9) | 10 | 10 | 100 | (72.2 - 100.0) |
| Up to two specimens | ||||||||
| Gastric aspirate | 14 | 22 | 63.6 | (43.0 - 80.3) | 267 | 269 | 99.3 | (97.3 - 99.8) |
| String | 8 | 12 | 66.7 | (39.1 - 86.2) | 265 | 267 | 99.3 | (97.3 - 99.8) |
| Induced sputum | 13 | 19 | 68.4 | (46.0 - 84.6) | 264 | 265 | 99.6 | (97.9 - 99.9) |
| Nasopharyngeal aspirate | 15 | 22 | 68.2 | (47.3 - 83.6) | 269 | 270 | 99.6 | (97.9 - 99.9) |
| Stool | 6 | 7 | 85.7 | (48.7 - 97.4) | 257 | 263 | 97.7 | (95.1 - 99.0) |
| Urine | 2 | 2 | 100 | (34.2 - 100.0) | 240 | 242 | 99.2 | (97.0 - 99.8) |
| FNAB | 2 | 5 | 40.0 | (11.8 - 76.9) | 6 | 6 | 100.0 | (61.0 - 100.0) |
*
Number of children with positive MGIT result on first specimen collected.
**
Number of children with valid MGIT result on first and/or second specimen collected. MGIT results that were contaminated or showed mycobacteria other than tuberculosis were excluded
FNAB = fine needle aspirate biopsy, MGIT = mycobacterial growth indicator tube