Improved Diagnostic Evaluation of Suspected Tuberculosis

Data are for patients in whom results on both tests were available (n = 265). Except where stated, values are likelihood ratios with 95% CIs. Tuberculin skin test thresholds for positivity were induration ≥15 mm on the Mantoux test or grade 3 to 4 on the Heaf test. ELISpot = enzyme-linked immunospot incorporating early secretory antigenic target-6 and culture filtrate protein-10; ELISpot^PLUS = enzyme-linked immunospot incorporating early secretory antigenic target-6, culture filtrate protein-10, and Rv3879c; TB = tuberculosis; TST = tuberculin skin testing. Top. ELISpot followed by TST. *Combined sensitivity of 1 or more positive results from tests used in combination, 97% (CI, 93% to 99%). †Combined specificity for a double-negative result from tests used in combination, 62% (CI, 53% to 71%). Bottom. ELISpot^PLUS followed by TST. ‡Combined sensitivity of 1 or more positive results from tests used in combination, 99% (CI, 95% to 100%). §Combined specificity for a double-negative result from tests used in combination, 61% (CI, 52% to 70%).