Influence of Bacille Calmette-Guerin Vaccination on Size of Tuberculin Skin Test Reaction: To What Size?

Abstract
Background. Previous bacillus Calmette-Guérin (BCG) vaccination can confound the results of a tuberculin skin test (TST). We sought to determine a cutoff diameter of TST induration beyond which the influence of BCG vaccination was negligible in evaluating potential Mycobacterium tuberculosis infection in a population of health care workers with a high vaccination rate and low incidence of tuberculosis.