Increased sensitivity of tests for the detection of blood group antigens in stains using a low ionic strength medium.

The incorporation of a low ionic strength solution (LISS) in the micro-elution technique used for the detection of blood group antigens in stains markedly improves the test's sensitivity. This is because LISS increases the amount of antibody taken up by the antigen in the stain which results in a greater yield of antibody recovered from the slain by elution. LISS also enhances the activity of the eluted antibody if it is introduced as a suspension medium for the red cells used to detect the antibody.The introduction of suitably diluted AB serum as diluent when testing the eluates is an additional advantage.The improvement in the sensitivity of the micro-elution technique is great enough in some instances to allow the detection of an antigen in a stain which is undetectable in the absence of LISS. Moreover some doubtful positive reactions are enhanced sufficiently for the presence of an antigen to be definitely established.