APTITUDE OF MONOCLONAL REAGENTS FOR TESTI NG BLOOD-GROUP ANTIGENS IN THE CASE OF A POSITIVE DIRECT ANTIGLOBULIN-TEST

Background: Monoclonal reagents of the IgM type allow to test some red blood cell antigens (K; Jk(a); Jk(b)) by the tube centrifugation meth od at room temperature, for the examination of which the indirect anti globulin test was necessary in the past. This permits to test antigens also when the direct antiglobulin test is positive, provided the sera do not contain too much supplement. Materials and Methods: We tested a choice of monoclonal reagents of different manufacturers (for the AB O system, A subgroups, the Rhesus, MN, Kell, Kidd and Lewis system) fo r their ability to examine antibody-coated erythrocytes, To recognize false-positive reactions of the reagents, erythrocytes without the par ticular antigen were coated with an incomplete antibody, and then the reagent was tested with these self-made Coombs control cells, Results: We found no false-positive reactions for all tested anti-A, anti-B, a nti-AB, and anti-Al reagents. Some anti-C, anti-c, anti-E, anti-e and anti-N reagents showed weak false-positive reactions, some anti-H. ant i-D, anti-K, anti-Jk(a), anti-Jk(b), anti-Le(a), anti-Le(b) and anti-M reagents stronger false-positive reactions, Conclusions: We therefore recommend that for the quality control of saline-reactive test sera t he ability for testing antibody-coated erythrocytes should be taken in to account additionally to the usual criteria (sensitivity, specificit y, titer, avidity).