Direct agglutination test

Apart from antibodies detected by (a) the schizont-infected red cell agglutination test, (b) the agglutination of sporozoites, (c) complement fixation, (d) passive hemagglutination and by the direct and indirect immunofluorescent methods [for review, see reference (V4)], malarial antibodies have also been detected by malarial antigens prepared from heavily infected human placenta, infected human brain, and short-term in vivo cultures of cells from heavily parasitized subjects (Wll) (see Tables 7 and 8). 

The direct Coombs test detects sensitization of RBCs to a drug in vivo by looking for the presence of polyclonal anti-RBC antibodies or complement on the surface of RBCs. A species-specific antibody reagent (AG) used on patient s EDTA blood detects agglutination of RBCs in a majority of cases of IMHA. Therefore, in a suspected case of drug-induced IMHA, fresh blood must be collected as soon as possible to conduct the direct Coombs test. This test is still the state of the art for the diagnosis of IMHA. In this specific test. 

The drug is readily attached to RBCs, which are then either directly agglutinated by antidrug antibody or, if the antibody is weak, it is revealed by a positive indirect Coombs test, e.g., penicillin. 

A case of disseminated intravascular coagulation has been described following repeated therapy with the antischistosomal anthelmintic, Stibophen, a trivalent antimony compound, (Fig. 8 c) (Weiss et al. 1972) and an occasional haemolytic anaemia or thrombocytopenia (Harris 1956 Kahn and Brod 1961 de Torre-grosa et al. 1963). In the former case, there was a weakly positive direct Coombs test and the patient s serum agglutinated both normal and the patient s red blood cells in the presence of Stibophen. In most instances, Stibophen-induced haemolytic anaemia appears to be associated with IgM antibody (Van Arsdel 1978). 

Direct agglutination reactions which are used in blood banking to test for erythrocyte blood group surface antigens. Specific blood group antisera are used. 

These are tests based on the aggregation of red blood cells and which are used for the detection of antigens on their surfaces. Agglutination occurs because of the cross linking of cells by antibodies directed against surface antigens. There are several different types ... 

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