Table 2.

Diagnostic Significance of K/T Ratio in Active TB Disease

IDO Activity for Diagnosing Active TB Disease
Cutoff	Sensitivity (%)	95% CI	Specificity (%)	95% CI	PPV (%)	NPV (%)
0.010	100	95–100	30	14–24	22	100
0.020	100	95–100	37	21–31	27	100
0.030	100	95–100	39	24–33	30	100
0.040	100	95–100	42	31–39	32	100
0.050	99	92–99	49	43–51	35	100
0.060	98	92–99	62	57–66	45	99
0.070	97	90–99	77	66–74	58	99
0.080	96	88–98	86	73–85	77	99
0.090	95	85–96	90	78–85	79	98
0.100	94	82–95	90	80–91	85	98
0.110	90	70–90	92	85–90	86	97
0.120	87	67–87	93	88–92	87	97
0.130	82	66–86	94	89–94	90	96
0.140	80	64–85	95	90–95	92	96
0.150	79	63–84	96	92–96	94	95

TB positives: All active TB cases at time of enrollment (n = 72). TB negatives: TB cases at time points other than TB diagnosis or labor, and controls at all times excluding labor (n = 510 specimens from women with HIV but no TB).

Abbreviations: CI, confidence interval; IDO, indoleamine 2,3-dioxygenase; NPV, negative predictive value; PPV, positive predictive value; TB, tuberculosis.