[The significance of tuberculin skin test in the investigation of mass outbreak of tuberculosis in schools].

A high school teacher was diagnosed as pulmonary tuberculosis. He was 27 years old and taught bookkeeping to the 1st year grade students in classes 3 and 6, the 2nd year grade students in classes 4 and 5. He was also the assistant teacher in charge of class 1 of the 3rd year grade students and the adviser of the badminton club in the school.