Risk of occupational tuberculosis in National Tuberculosis Programme laboratories in Korea.

SETTING

Mycobacteriology laboratories in the National Tuberculosis Control Programme in Korea.

OBJECTIVES

To determine tuberculosis (TB) risk by type of work among laboratory workers compared to non-laboratory workers.

DESIGN

Retrospective study of TB incidence among technicians involved in acid-fast bacilli smear microscopy or culture and/or drug susceptibility testing (DST) compared with that among managerial/clerical workers.

RESULTS

Two cases developed among 77 non-laboratory workers, two among 88 smear microscopy technicians, and 11 among 76 culture/DST technicians during the observation period. Compared to non-laboratory workers, the relative risk of TB was 1.4 (95% CI 0.2-10.0) among microscopy technicians and 7.8 (95% CI 1.7-34.9) among culture/DST technicians. TB developed among 7/15 DST technicians compared to only 2/59 culture/non-DST technicians. Compared to non-laboratory workers, the relative risk for DST technicians was 21.5 (95% CI 4.5-102.5).

CONCLUSION

DST led to the highest relative risk among all types of mycobacteriology work, while performing smear microscopy alone did not pose an elevated risk compared to clerical work.