DIRECT ANTIGLOBULIN TEST

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Specimen: 5 mL blood in EDTA tube.

Method: Polyspecific anti-human globulin serum added to patient’s washed red cells; the test is positive if agglutination is observed.

Application: Investigation of possible immune haemolysis. Detection of antibody and/or complement on red cell surface.

Investigation: Positive results are seen in autoimmune haemolysis, haemolytic disease of the newborn, incompatible transfusion reactions, drug-induced immune haemolysis. Monospecific antisera indicate whether IgG, IgM, IgA and/or complement is attached to red cells. Occasionally a weak, non-specific positive result due to artefactual ex vivo fixation of complement can be seen in otherwise normal individuals.

Reference: Ford D. Aust J Med Lab Sci 1995; 16: 67-70.

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