Semi-Quantitative Complement Fixation
This test is New York DOH approved.
An antibody titer greater than or equal to 1:8 is generally considered presumptive evidence of histoplasmosis. Greater than 1:32 or rising titers indicate strong presumptive evidence of histoplasmosis.
Yeast phase is regarded as more sensitive. Approximately 90-95 percent of cases have positive titers to one or both antigens. Titers to mycelial antigen are higher in chronic infection. Cross-reactions, usually at lower titers, may occur with other fungal disease. Rising titers suggest progression of infection. Skin tests in individuals previously exposed may cause titer elevation in 17-20 percent of cases.
Negative fungal serology does not rule out the possibility of current infection.