Table 2.
Performance of the Gen-Probe's Amplified MTD test compared with M. tuberculosis culture results
| Specimen type (no.) | Culture result (no.)e |
% sensitivity (95% CI)d | % specificity (95% CI)d | Amended result (%)c |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Positive |
Negative |
Sensitivity (95% CI)d | Specificity (95% CI)d | |||||||||||||
| Smear positive |
Smear negative |
Smear positive |
Smear negative |
|||||||||||||
| MTD + | MTD − | Equivocal | MTD + | MTD − | Equivocal | MTD + | MTD − | Equivocal | MTD + | MTD − | Equivocal | |||||
| Respiratory (131) | 44 | 0 | 1 | 17 | 2 | 3 | 2 | 6a | 1 | 3 | 46b | 6 | 96.8 (89.1–99.0) | 91.2 (81.1–96.2) | 98.4 (91.5–99.7) | 93 (83.3–97.2) |
| Nonrespiratory (31) | 4 | 0 | 0 | 8 | 0 | 2 | 2 | 3 | 0 | 2 | 6 | 4 | 100 (75.8–100) | 69.2 (42.3–87.3) | 100 (79.6–100) | 90 (59.6–98.2) |
| CSF (7) | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | 0 | 1 | 0 | 1 | 100 (34.2–100) | 75 (30.1–95.4) | ||
| Gastric aspirate (5) | 1 | 0 | 0 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 100 (51.0–100) | 100 (20.7–100) | ||
| Urine (3) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 0 | 100 (20.7–100) | |||
| Fluid (6) | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 3 | 100 (20.7–100) | 100 (34.2–100) | ||
| Miscellaneous (10) | 2 | 0 | 0 | 3 | 0 | 2 | 2 | 0 | 0 | 1 | 0 | 0 | 100 (56.5–100) | 66.7 (20.8–93.9) | 100 (61–100) | |
a
All six cultures grew Mycobacteria other than M. tuberculosis.
b
Seven of these cultures grew Mycobacteria other than M. tuberculosis.
c
Amended results based on clinical diagnosis as the gold standard. Clinical diagnosis was based on patient symptoms, chest X-rays, and use of anti-TB treatment.
d
CI, confidence interval.
e
+, positive; −, negative.