A clinical evaluation of the diagnostic usefulness of an early dermal reaction to tuberculin: a failure to distinguish between tuberculosis and other respiratory disease.

An early (6-8 hour) reaction to RT23 tuberculin which was previously found to distinguish between patients with active tuberculosis and healthy tuberculin positive individuals failed to distinguish between such patients and those with other respiratory diseases. It also failed to distinguish between radiologically active and inactive cases of tuberculosis. Such early reactions were frequent among healthy hospital workers but not among other healthy subjects.