Standardization of a Hemagglutination Test for Schistosomiasis with Formalin-Treated Human Erythrocytes*

Abstract A hemagglutination test for Manson's schistosomiasis has been made practical by the use of tanned, formalin-treated human erythrocytes sensitized with adult-worm extracts. Such sensitized cells are stable and can be kept for months at 4°C, -20°C, or freeze-dried. No previous serum absorptions are necessary, and tests, performed in perspex plates, can be done with serum dilutions or eluates from blood samples collected on filter paper by finger-prick. Such samples can be sent by post to the laboratory. All such features make the test practical for routine work. To standardize the test, we evaluated factors influencing the results. These showed good reproducibility, differences in titers of two dilutions being considered as significant. A sensitivity of 96% was found in a group of 100 patients with schistosomiasis, with only 2.6% of positive results in 152 normal persons. Titer variations were followed in a few patients after specific therapy.