Table 3. Performance of the urine TB-LAM test in the diagnosis of smear-negative TB stratified by CD4 cell count.
| Overall accuracy (95% CI) | Accuracy among patients with CD4<100 (95% CI | |
|---|---|---|
| Urine TB-LAM test | N = 417 | N = 201 |
| Sensitivity | 37.5 (27.8–48.0) | 55.2 (41.5–68.3) |
| Specificity | 93.1 (89.8–95.7) | 89.5 (83.3–94.0) |
| PPV | 62.1 (48.4–74.5) | 68.1 (52.9–80.9) |
| NPV | 83.3 (79.0–87.0) | 83.1 (76.2–88.7) |
| LR (positive) | 5.47 (3.39–8.83) | 5.26 (3.09–8.95) |
| LR (negative) | 0.67 (0.57–0.79) | 0.50 (0.37–0.67) |
| Combination of Urine TB-LAM test and CXR | N = 381 | N = 174 |
| Sensitivity | 50.0 (39.0–61.0) | 70.8 (55.9–83.0) |
| Specificity | 86.1 (81.6–89.8) | 84.1 (76.6–90.0) |
| PPV | 51.2 (40.0–62.3) | 63.0 (48.7–75.7) |
| NPV | 85.5 (81.0–89.3) | 88.3 (81.2–93.5) |
| LR (positive) | 3.60 (2.52–5.13) | 4.46 (2.87–6.94) |
| LR (Negative) | 0.58 (0.47–0.72) | 0.35 (0.22–0.54) |
Abbreviations: TB, tuberculosis; LAM, lipoarabinomannan; CXR, Chest X-ray; PPV, positive predictive value; NPV, negative predictive value; LR, likelihood ratio