Table 3.
Performance characteristics of combinations of elements in predicting TB
| Sensitivity % (95%CI) | Specificity % (95%CI) | PPV % (95%CI) | NPV % (95%CI) | LR-positive % (95%CI)* | LR-negative % (95%CI)* | |
|---|---|---|---|---|---|---|
| SOC TB | 54 (40–67) | 76 (72–80) | 24 (17–32) | 92 (89–95) | 2.26 (1.67–3.06) | 0.61 (0.45–0.81) |
| Any of 4 symptoms | 91 (80–97) | 21 (17–25) | 14 (10–18) | 94 (87–98) | 1.14 (1.04–1.26) | 0.45 (0.19–1.06) |
| Any of 4 symptoms + positive smear | 9 (3–20) | 98 (97–99) | 44 (17–77) | 89 (85–92) | 6.03 (1.91–19.1) | 0.92 (0.85–1.00) |
| Any of 4 symptoms + CXR | 50 (36–64) | 78 (74–82) | 24 (16–33) | 92 (88–95) | 2.27 (1.64–3.15) | 0.64 (0.49–0.84) |
| Any of 4 symptoms + CXR compatible with TB | 44 (31–59) | 84 (80–87) | 27 (18–38) | 92 (88–94) | 2.72 (1.87–3.94) | 0.66 (0.52–0.85) |
| Cough or lymphadenopathy | 93 (82–98) | 25 (21–29) | 15 (11–19) | 96 (90–99) | 1.23 (1.12–1.35) | 0.30 (0.11–0.78) |
| Cough or lymphadenopathy + CXR | 54 (40–67) | 78 (73–82) | 25 (17–34) | 92 (89–95) | 2.41 (1.77–3.29) | 0.60 (0.45–0.80) |
| Cough or lymphadenopathy + CXR compatible with TB | 48 (34–62) | 83 (79–87) | 29 (20–39) | 92 (89–95) | 2.90 (2.03–4.13) | 0.62 (0.48–0.81) |
| Any of 4 or lymphadenopathy | 96 (87–99) | 16 (13–20) | 14 (10–18) | 97 (89–99) | 1.15 (1.07–1.23) | 0.23 (0.06–0.92) |
| Any of 4 or lymphadenopathy + CXR | 54 (40–67) | 77 (73–81) | 24 (17–33) | 92 (89–95) | 2.33 (1.72–3.17) | 0.60 (0.45–0.81) |
| Any of 4 or lymphadenopathy + CXR compatible with TB | 48 (34–62) | 83 (79–87) | 28 (19–38) | 92 (89–95) | 2.81 (1.98–4.00) | 0.63 (0.48–0.81) |
| Any of 4 symptoms or CD4 < 200 | 98 (90–100) | 18 (15–22) | 14 (11–18) | 99 (93–100) | 1.20 (1.13–1.27) | 0.10 (0.01–0.72) |
| Any of 4 symptoms or CD4 < 200 + CXR | 54 (40–67) | 77 (73–81) | 25 (17–33) | 92 (89–95) | 2.36 (1.73–3.21) | 0.60 (0.45–0.80) |
| Any of 4 symptoms or CD4 < 200 + CXR compatible with TB | 48 (34–62) | 83 (79–87) | 28 (19–38) | 92 (89–95) | 2.81 (1.98–4.00) | 0.63 (0.48–0.81) |
*
Negative LR = (1 − sensitivity) ÷ specificity; positive LR = sensitivity ÷ (1 − specificity).
TB = tuberculosis; CI = confidence interval; PPV = positive predictive value; NPV = negative predictive value; LR = likelihood ratio; SOC = standard of care; AFB = acid-fast bacilli; BMI = body mass index; CXR = chest radiograph.