Table 3.

IGRA^a test results for DST and MDT reagents.

Animal group	Test performance	DSTb	MDTb	B–Ac
Experimentally infected (n = 19)	% Sensitivity [95% CI]	63 [41, 81]	100 [83, 100]*	100 [83, 100]
Naturally infected (n = 22)	% Sensitivity [95% CI]	68 [47, 84]	100 [85, 100]*	100 [85, 100]
Non-infected controls (n = 59)	% Specificity [95% CI]	100 [94, 100]	97 [88, 99]	97 [88, 99]
Gudair vaccinated (n = 29)	% Specificity [95% CI]	100 [88, 100]	97 [83, 100]	100 [88,100]

*p < 0.05, McNemar’s test (compared to DST).

^aIGRA, interferon-gamma release assay using the BOVIGAM IFN-γ EIA kit.

^bDST (DIVA Skin Test) or MDT (Molecularly Defined Tuberculin) induced IFN-γ production. Cut-off for positivity = OD450 nm with MDT or DST minus nil antigen control > 0.1.

^cB–A, comparison of IFN-γ induced by stimulation with PPD-B and PPD-A. Cut-off for positivity = OD450 for PPD-B minus PPD-A > 0.1.