ABSTRACT
This paper gives the results of studies on various technical aspects of the indirect haemagglutination (IHA) test for malaria, on the similarity of the results obtained in the IHA test and in the indirect fluorescent antibody test, on the use of various plasmodial extracts as sensitizing antigens in the IHA test, and on the influence of heterophile antibodies on the titres obtained in the IHA test. Some longitudinal observations on induced malaria infections of man and monkey showed that the infection can induce the production of heterophile antibodies: their appearance, however, remains unpredictable. In some infections agglutinins against host erythrocyte components are also produced. Absorption of sera with tanned sheep cells sensitized with noninfected host red blood cell antigens is advocated as a control on the IHA titre for specific agglutinins.
