Table 3.

Sensitivities, specificities and positive predictive values for tuberculosis within one year postpartum associated with cut-off values in CD4 cell count alone and in combination with IFN-γ responses measured at 32 weeks’ gestation in HIV-1 infected women

Predictor cut-off value		Events	PYFU	Sensitivity*	Specificity	Positive Predictive value	Hazard Ratio** (95% CI)	p-value
CD4 cell count
<250		4	44.4	51.5 (14.1–91.7)	82.8 (78.4–87.0)	9.0 (2.5–23.1)	4.7 (1.2–18.6)	0.03
<350		5	84.4	64.6 (24.6–100.0)	64.7 (59.3–69.8)	5.9 (1.9–13.8)	3.3 (0.8–13.7)	0.10
CD4 cell count	IFN-γ
≥250	>0	3	137.5	78.0	33.4 (27.3–39.5)	2.2 (0.4–6.4)	1.5 (0.2–14.4)	0.73
	≥ 6	3	98.9	76.3	53.5(47.1–59.8)	3.0 (0.6–8.9)	3.3 (0.3–31.6)	0.30
	≥ 10	2	85.4	47.5	59.2(53.3–65.2)	2.3 (0.3–8.5)	1.4 (0.2–10.1)	0.72
<250	>0	3	21.7	84.6	47.7(33.8–61.4)	13.8 (2.9–40.4)	3.2 (0.3–30.7)	0.32
	≥ 6	3	15.6	89.4	63.3(50.4–78.4)	19.2 (4.0–56.2)	5.8 (0.6–55.9)	0.13
	≥ 10	3	13.6	87.5	68.8(56.0–82.2)	22.1 (4.5–64.5)	7.0 (0.7–67.8)	0.09
≥350	>0	2	113.7	74.5	30.3(24.1–36.2)	1.8 (0.2–6.4)	1.0 (0.1–10.6)	0.97
	≥ 6	2	81.1	73.8	51.0(44.0–58.2)	2.5 (0.3–8.9)	2.2 (0.2–23.8)	0.53
	≥ 10	1	69.5	35.6	57.3(50.5–64.1)	1.4 (0.04–8.0)	0.7 (0.1–7.8)	0.78
<350	>0	4	45.5	80.8	45.9(36.8–55.8)	8.8 (2.4–22.5)	3.4 (0.4–30.5)	0.27
	≥ 6	4	33.5	78.9	62.3(54.0–71.7)	11.9 (3.3–30.6)	6.0 (0.7–54.1)	0.11
	≥ 10	4	29.4	79.4	67.0(57.6–75.7)	13.6 (3.7–34.8)	7.4 (0.8–66.1)	0.07

Note: PYFU Person years of follow-up;

^*Confidence Intervals for sensitivity could not be calculated due to the very small number of events that the sensitivity estimate was based on.

^**Crude Hazard Ratio for active TB in women below CD4 cut-off value compared with women above CD4 cut-off value