Two-step tuberculin testing in a veterans domiciliary population

Seven hundred ninety-six veterans were scheduled for tuberculin testing during a hospital/domiciliary employee health program in southern Ohio. The Mantoux test, using 5 TU of commercial purified protein derivative (PPD) was used. Nonsignificant reactors were retested at one week to detect and quantitate the "booster phenomenon," following Centers for Disease Control (CDC) recommendations. Cost data were recorded. The initial frequency of 39.3% reactions greater than 10 mm in 740 tested subjects increased to 46.7% on two-step testing. Fifty-five of 414 subjects exhibited the booster effect, a rate intermediate between that reported in Alabama and no boosting reported in Rochester, New York. Costs of two-step testing exceeded, by a small margin, estimated costs of isoniazid preventive therapy for apparent converters detected by two-step testing.