Tuberculin Skin Testing in San Francisco Schools As An Instrument of Tuberculosis Casefinding

A Five Year Study

¹ Tuberculosis Control Division, Department of Public Health, City and County of San Francisco

Since 1956 tuberculin skin testing has been done annually in all 202 public and parochial schools in San Francisco. The first, seventh, tenth and twelfth grades and all students recently moved to the City were tested. Of 134,458 students tested, 7,715, (5.7 per cent), were reactors. Whereas, participation in the program is voluntary, the follow-up of all reactors and their immediate family group was mandatory in order to exclude the possibility of active communicable disease in the community. As a result, 212 cases of tuberculosis were found in students and 105 cases in family contacts; or 41.2 cases of active tuberculosis per thousand reactor found. This stands out in sharp contrast to the casefinding rate of 2.4 per thousand tests given and emphasizes the importance of the follow-up of reactors and their immediate family group.

Of the 212 student cases, 125 were primary tuberculosis, of which 105 were in elementary grades and 19 in junior high school. There were 64 cases of communicable pulmonary tuberculosis found in the senior and junior high schools and none in the elementary grades. Extrapulmonary tuberculosis was found in 23 students. Of the student cases 79.4 per cent were in non-whites and Latin-Americans. The percentage of reactors at the twelfth grade level was reduced from 19.9 in 1956 to 12.7 in 1961; and at the first grade level from 3.9 in 1956 to 2.7 in 1961.