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The Direct Coombs/Antiglobulin test (DCT) was originally described by Coombs, Moorant and Race in 1945. The principle of the test is to demonstrate antibodies or complement coating red cells invivo by using Antihuman globulin (AHG) or Coombs reagent.

Till date it remains the hallmark for the diagnosis of immune hemolytic anemias. Technically various modifications in the procedure have been described to bring about added sensitivity to the DCT. Some of these changes include: use of more specific reagents like monospecific AHGs (e.g. against IgG or C3) and Enzyme elution of the antibodies from the red cells. In practice, it was noted that DCT required technical expertise (esp steps of washing the red cells, effective centrifugation etc.) for proper interpretation.

In 1990 Lappierre introduced the novel ‘GEL’ method to demonstrate antibodies or complement coated red cells. The gel system is based on the principle that the Sephadex gel matrix acts as a sieve, through which agglutinates of RBCs are too large to pass though and remain entrapped in the gel, depending on their size. A negative reaction is seen as a clear pellet of cells settled at the bottom of the microtube. Grading of the reactions can be done according to the distribution of RBCs agglutinates through the gel column. This technique was easier to perform and did not require technical skill, thereby overcoming the practical difficulties of performing DCTs.

In this context we have tried to evaluate three of the methods used for the interpretation of DCT gel coombs card.