Table 4. Performance of the urine TB-LAM test in the diagnosis of smear-negative TB among inpatients and outpatients stratified by CD4 cell count.
| Overall accuracy(95% CI) | Accuracy among patients with CD4<100 (95% CI) | |||
|---|---|---|---|---|
| Inpatients | outpatients | Inpatients | Outpatients | |
| Urine TB-LAM | N = 287 | N = 130 | N = 169 | N = 32 |
| Sensitivity | 39.0 (28.0–50.8) | 31.6 (12.6–56.6) | 54.2 (39.2–68.6) | 60.0 (26.2–87.8) |
| Specificity | 90.0 (85.1–93.7) | 99.1 (95.1–100.0) | 87.6 (80.4–92.9) | 100.0 (84.6–100.0) |
| PPV | 58.8 (44.2–72.4) | 85.7 (42.1–99.6) | 63.4 (46.9–77.9) | 100.0 (54.1–100.0) |
| NPV | 80.1 (74.4–85.0) | 89.4 (82.6–94.3) | 82.8 (75.1–88.9) | 84.6 (65.1–95.6) |
| LR (positive) | 3.90 (2.38–6.38) | 35.05 (4.47–275.1) | 4.37 (2.55–7.50) | N/A |
| LR (negative) | 0.68 (0.56–0.82) | 0.69 (0.51–0.94) | 0.52 (0.38–0.72) | 0.40 (0.19–0.85) |
| Combination of Urine TB-LAM and CXR | N = 256 | N = 125 | N = 144 | N = 30 |
| Sensitivity | 52.9 (40.4–65.2) | 38.9 (17.3–64.3) | 71.8 (55.1–85.0) | 66.7 (29.9–92.5) |
| Specificity | 84.0 (78.0–89.0) | 89.7 (82.3–94.8) | 81.0 (72.1–88.0) | 100.0 (83.9–100.0) |
| PPV | 54.5 (41.8–66.9) | 38.9 (17.3–64.3) | 58.3 (43.2–72.4) | 100.0 (54.1–100.0) |
| NPV | 83.2 (77.1–88.2) | 89.7 (82.3–94.8) | 88.5 (80.4–94.1) | 87.5 (67.6–97.3) |
| LR (positive) | 3.32 (2.23–4.94) | 3.78 (1.69–8.46) | 3.77 (2.43–5.86) | N/A |
| LR (Negative) | 0.56 (0.43–0.73) | 0.68 (0.47–0.99) | 0.35 (0.21–0.58) | 0.33 (0.13–0.84) |
Abbreviations: TB, tuberculosis; LAM, lipoarabinomannan; CXR, Chest X-ray; PPV, positive predictive value; NPV, negative predictive value; LR, likelihood ratio