Significance of the gel diffusion precipitin test for invasive amoebiasis.

The double diffusion precipitinin test for amoebiasis, has been evaluated in invasive amoebiasis. It gave positive percentages of 91-3 and 90-0 in cases of amoebic liver abscess and amoebic dysentery. False positive rates of 8-0 per cent and 0-0 per cent were obtained in miscellaneous non-amoebic disorders and in apparently healthy subjects, respectively. Its comparison with the indirect haemagglutination test revealed it to be slightly less sensitive but more specific. The agar gel precipitinin test became positive whenever the indirect haemagglutination titres were 1:256 or more. The adsorption studies revealed that both tests detected different types of antibodies. The use of the gel diffusion test is recommended as a routine method for amoebiasis as it is simple to perform in areas where sophisticated laboratory methods are not available.