The frequency profile of tuberculin skin testing among employees of a hospital was studied. In the analysis, tuberculin skin testing was defined as “negative” if skin rash is measured ≤ 9mm, and as “positive” if skin rash is measured ≥ 10mm, and as “strongly positive” if skin rash is measured ≥ 10mm, with induration, and double skin rash or bulla. Boosting was defined as initial skin rash was measured ≤ 9mm, with second skin rash measured ≥ 10mm and at least 6 mm increase of rash than the initial one.
544 employees were tested initially, and 81 were retested. Initial tuberculin positivity was associated with older age (p<0.001) but boosting was not associated with age and occupation. Comparing pharmacists with other groups, the adjusted odds ratio of an initial strongly positive tuberculin reaction as significantly higher, namely 2.8 (95% confidence interval 1.2-6.7), but that of a booster reaction was 4.8 (0.7-32.1) which was insignificant.
