A New Solid-Phase Method for ABO Grouping, Rh Phenotyping, and Kell Determination

Abstract

Background: In comparison with a well established agglutination method, a newly developed solid-phase method for ABO grouping, Rh phenotyping, and Kell determination was examined for its suitability in routine testing. This new 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 the prepared wells and are allowed to react immunologically with the solid phase. Positive reactions are indicated by the adherence of red blood cells over the entire surface of the wells, whereas negative reactions form discrete red blood cell buttons in the center of the wells. The uniformity of the reaction patterns permits an objective reading of the results, both visually and spectrophotometrically. Material and Methods:Blood samples of 631 healthy blood donors and 237 patient samples were determined by the solid-phase method, and the results were compared with those obtained by the conventional agglutination test. In addition, a panel of weak A and B subgroups and D variants was determined. Results:Determining the ABO blood groups as well as the Rh phenotypes and the Kell antigen, we found complete accordance between both methods. Detecting A and B subgroups and D variants, the solid-phase method was found to be more sensitive when compared with the agglutination method. Conclusions:Due to the ease of handling of the new solid-phase assay and the unequivocal test results, the method is suitable for manual 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 refrigerator, the results remain stable for several days.