Radioallergosorbent and indirect fluorescent antibody tests in immunodiagnosis of schistosomiasis.

Radioallergosorbent tests for specific IgE antibodies to Schistosoma haematobium and S. mansoni were positive in 82 and 72%, respectively, of sera from 136 African schistosomiasis patients. 99% of sera from controls (5 free of parasitic disease, 75 infested with hookworm, Ascaris, Trichuris, and/or Onchocerca) were negative. When titres in indirect fluorescent antibody tests were set at the same level of specificity only 38% of patients' sera were positive. A cut-off at a higher concentration increased sensitivity to 65% but lowered specificity (10% controls positive).