TABLE 3.
Diagnostic performance of the TB assays according to the categories of TB
| Case definition | Sensitivity % (n/N, 95% CI) |
Specificity % (n/N, 95% CI) |
PPVa % (n/N, 95% CI) |
NPV % (n/N, 95% CI) |
Positive likelihood Ratio (95% CI) |
Negative likelihood Ratio (95% CI) |
|---|---|---|---|---|---|---|
| Confirmed TB (n = 99b)versus not TB (n = 144) | ||||||
| SLIM oral swab | 65 (64/99, 54–74) | 86 (124/144, 79–91) | 76 (64/84, 68–83) | 78 (124/159, 73–82) | 4.66 (3.02–7.17) | 0.41 (0.31–0.54) |
| Xpert MTB/RIF | 54 (51/95, 43–64) | 100 (130/130, 97–100) | 100 (51/51) | 75 (130/174, 70–79) | Not applicable | 0.46 (0.37–0.58) |
| AFB smear | 35 (35/99, 26–46) | 92 (127/138, 86–96) | 76 (35/46, 63–86) | 66 (127/191, 63–70) | 4.44 (2.37–8.30) | 0.70 (0.60–0.82) |
| MTB culture | 94 (93/99, 87–98) | 100 (138/138, 97–100) | 100 (93/93) | 96 (138/144, 91–98) | Not applicable | 0.06 (0.03–0.13) |
| Possible TB (n = 29) versus not TB (n = 144) | ||||||
| SLIM oral swab | 69 (20/29, 49–85) | 86 (124/144, 79–91) | 50 (20/40, 38–62) | 93 (124/133, 89–96) | 4.978 (3.09–7.98) | 0.36 (0.21–0.62) |
| Xpert MTB/RIF | 7 (2/27, 1–24) | 100 (130/130, 97–100) | 100 (2/2) | 84 (130/155, 82–85) | Not applicable | 0.93 (0.83–1.03) |
| AFB smear | 0 (0/28c, 0–12) | 92 (127/138, 86–96) | 0 (0/11) | 82 (127/155, 81–83) | 0.00 | 1.09 (1.04–1.14) |
| MTB culture | 0 (0/28c, 0–12) | 100 (138/138, 97–100) | Not applicable | 83 (138/166, 83–83) | Not applicable | 1.00 (1.00–1.00) |
a
PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval; AFB, acid-fast bacilli; MTB, Mycobacterium tuberculosis.
b
Six participants with TB not isolated in sputum but isolated from bronchial washing fluid were included.
c
One participant without a sputum exam was included. See Fig. 2 for more details.