Table 1.

Proportions of individuals with positive IFN-γ responses to ESAT-6, PPD, and PHA and positive tuberculin skin tests

TestaNo. of responders/total no. of individuals (%)Pb
Community controlsHousehold contactsTuberculosis patients
TST11/29 (38)24/28 (86)27/29 (93)<0.001
PPD27/30 (90)23/28 (82)25/30 (83)0.68
ESAT-69/30 (30)20/28 (71)13/30 (43)0.004
PHA28/30 (93)27/28 (96)27/30 (90)0.03
  • a TST, tuberculin skin test. TST was considered positive when the skin induration was equal to or greater than 10 mm. A positive IFN-γ response was defined as an IFN-γ concentration in the stimulated sample above the mean plus 3 standard deviations of the control samples (medium alone).

  • b P values are based on comparisons of three groups, adjusted for age, sex, ethnic group, and BCG scar status.