The value of the skin test and complement fixation test in the diagnosis of chronic pulmonary histoplasmosis.

Histoplasmin skin test results in patients with chronic pulmonary histoplasmosis from Missouri and Texas were compared to results in a previous study of U.S. Navy recruits. When consideration was given to geographic areas from which persons from each group were admitted to the study, it was found that the recruits were as likely to have a positive skin test as were those with the disease. In a similar manner, the Texas histoplasmosis patients were compared to groups of patients from that state with chronic obstructive pulmonary disease and with pulmonary tuberculosis. Again, no significant differences were found. It was concluded that the histoplasmin skin test is not of value in the diagnosis of chronic pulmonary histoplasmosis. Histoplasmosis complement fixation test data from the chronic pulmonary histoplasmosis group were compared to data from the chronic obstructive pulmonary disease and pulmonary tuberculosis groups. The usefulness of the complement fixation test in chronic pulmonary histoplasmosis is limited, as with any test, by false-positive and false-negative reactions. A decision theory method was used to define the limits of usefulness.