A new solid-phase method far ABO grouping, Rh phenotyping, and Kell determination

Background: In comparison with a well established agglutination method, a n ewly developed solid-phase method for ABO grouping, Ph phenotyping, and Kel t determination was examined for its suitability in routine testing. This n ew method is characterized by the use of monoclonal IgM antibodies of blood group specificities which are immobilized onto the polystyrene microplate wells during the test procedure. Red blood cell suspensions are added to th e prepared welts and are allowed to react immunologically with the solid ph ase. Positive reactions are indicated by the adherence of red blood cells o ver the entire surface of the welts, whereas negative reactions form discre te red blood cell buttons in the center of the wells. The uniformity of the reaction patterns permits an objective reading of the results, both visual ly and spectrophotometrically. Material and Methods: Blood samples of 631 h ealthy blood donors and 237 patient samples were determined by the solid-ph ase method, and the results were compared with those obtained by the conven tional agglutination test. In addition, a panel of weak A and B subgroups a nd D variants was determined. Results: Determining the ABO blood groups as well as the Rh phenotypes and the Kell antigen, we found complete accordanc e between both methods. Detecting A and B subgroups and D variants, the sol id-phase method was found to be more sensitive when compared with the agglu tination method. Conclusions: Due to the ease of handling of the new solid- phase assay and the unequivocal test results, the method is suitable for ma nual routine testing in small- to medium-sized laboratories as well as for automation. The reaction patterns can easily be interpreted visually or by computer software-supported readers. Storing the microplates in a refrigera tor, the results remain stable for several days.