Weak D antigen testing using the groupamatic system.
Reliable detection of the weak D (Du) antigen has been a problem for the Groupamatic typing equipment. Using several anti-D sera of known concentration and Du red cells, dose-response curves produced by the Groupamatic revealed variation in the ability to detect the Du antigen by commercial anti-D reagents. Variation in the reactivity of the Du antigen among Du-positive donors was noted. Studies were conducted to determine optimal conditions for the Groupamatic to detect the weakest Du cells. When these conditions were applied to the retesting, 28 cell samples previously found falsely negative by a number of blood centers were accurately detected.
Blood Grouping and Crossmatching↗