Comparison of immunodiffusion and complement fixation tests in the diagnosis of histoplasmosis.

The immunodiffusion and complement fixation tests for histoplasmosis were compared on 2,090 initial sera from 70 proven cases of histoplasmosis, 177 routine chest hospital patients, and 1,843 coal miners from outside the major endemic area for histoplasmosis. The complement fixation test using histoplasmin as antigen detected antibodies in the sera of 72.8% of the 70 proven cases, while the complement fixation test using yeast antigen detected antibodies in 94.3% of the case sera, and the immunodiffusion test using histoplasmin antigen detected antibodies in 90% of the sera. The tests were also compared for sensitivity, specificity, and ease of performance.