Clinical significance of the anti‐complement component of antiglobulin antisera

Abstract
The need for anti‐complement (anti‐C') activity in antiglobulin antisera (AHG) for the detection of clinically significant antibodies was evaluated during a three‐year period. While performing routine compatibility testing using standard blood banking procedures, eight patients were found whose antibodies were detectable primarily or only by AHG containing anti‐C' activity; monospecific anti‐igG AHG gave weak or negative reactions. Seven of the antibodies were anti‐jka or jkb. Two of the anti‐jka antibodies were responsible for clinically unsuspected delayed hemolytic transfusion reactions. The anti‐jkb antibody resulted in a shortened survival of incompatible 51Cr‐labelled red blood cells. The incidence of such “complement‐only” Kidd antibodies was 23 percent of all Kidd antibodies found. These data suggest that the omission of anti‐C' in AHG in routine compatability testing could result in substantial risk of failure to detect clinically significant antibodies.