Immunocytochemical determination of ABH and MN antigens on dried blood traces in the nanoliter range.

The absorption-elution test and the mixed cell agglutination reaction are both ultimately based on the ability of indicator cells to agglutinate. This agglutination reaction requires a relatively large amount of antigenic epitopes, and, in addition, a relatively high volume of blood traces. The immunocytochemical demonstration of epitopes requires a lower volume, which, however must be fixed for investigation, thus possibly causing damage to the epitopes and thereby preventing detection. An immunocytochemical method is presented which permits ABH and MN antigen determination on dried blood traces of nanoliter quantities without special fixation. This method is based on immunocytochemical demonstration of antigens directly on the cell membrane in combination with the use of a coated glass slide that ensures maximum economy of epitopes.