Evaluation of the indirect immunofluorescence and complement fixation tests for the serodiagnosis of schistosomiasis

Sera from patients with a variety of infections were used to compare the sensitivity and specificity of the complement fixation (CF) and the indirect immunofluorescence (IIF) tests for schistosomiasis. Adult antigens were used in both tests. The sensitivities of the IIF and CF tests were 95% and 69%, respectively; the specificities were 98% and 100%, respectively. There was no statistical difference between the number of positive reactors among those individuals with no detectable helminth infection and those infected with helminths other than schistosomes. Infected people native to endemic areas had lower reactivity in both tests than did infected U.S. citizens who resided in endemic areas for only a few years. We concluded that the IIF test with adult antigen was more sensitive than and as specific as the CF test; therefore, the IIF test is the procedure of choice for routine diagnostic serology of schistosomiasis.