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A previous report from our institution showed that the use of a two-step tuberculin testing program in new employees reduced the apparent rate of conversion in annual skin testing by eliminating the effect of the booster phenomenon. However, the converter rate subsequently remained too high. We propose that the use of 10 mm of induration as the cutting point gave a high rate of false conversion in our area of high prevalence of sensitivity to nontuberculous mycobacteria. A change to 15 mm of duration as the cutting point reduced our conversion rate from 2.6 to 1.2%, identified a group who demonstrated continued large tuberculin reactions at repeat testing, and eliminated age dependency from our converter population. We propose the choice of 15 mm of induration as the appropriate cutting point in annual employee tuberculin skin testing programs in areas in which sensitivity to nontuberculous mycobacteria is common.

The speed and accuracy of diagnosis of tuberculosis on general medical teaching services were retrospectively compared to that on a designated publicly funded tuberculosis service and to recent discouraging reports in the literature. The diagnosis was confirmed in all patients on the designated service and in 78.8% of patients not on the designated service within one week. No patient was discharged undiagnosed. Acid-fast smears done by the hospital laboratory showed a sensitivity of 82.5% and a specificity of 98.4%. Radiologic reports indicated the presence of tuberculosis or cavities in 85% of chest x-ray films in patients with pulmonary disease. These results may indicate that a publicly funded tuberculosis service, by providing emphasis on tuberculosis, allows more rapid and accurate diagnosis of tuberculosis in all patients. The impact of such training on future health care delivery should be recognized when decisions regarding allocation of public funds are made.