Increased rate of tuberculin skin test conversion among workers at a university hospital.

Objectives: To summarize the results of an investigation of increased rates of tuberculin skin test conversion in employees at a university hospital.
Design: The results of annual tuberculin skin tests performed on all 1,845 hospital employees from 1986 to 1991 were reviewed.
Setting: A 450-bed acute tertiary care university hospital.
Results: The rate of tuberculin skin test conversion was 0.35% (standard deviation +/- 0.15) from 1986 to 1989 and increased to 1.7% during 1991. Investigation revealed deviations from the Centers for Disease Control (CDC) guidelines for tuberculosis control, which included the failure to consider tuberculosis as a probable cause of community-acquired pneumonia and the failure to initiate isolation precautions when tuberculosis was suspected.
Conclusions: The epidemic appeared to be secondary to delays in diagnosis and isolation of patients with pulmonary tuberculosis. Future control measures should include isolation of all hospital patients admitted with pneumonia until tuberculosis has been excluded.