[External national quality control of blood group typing 1983-92. Significance for quality assurance in transfusion medicine].

A programme for external quality control in blood group serology has been run in Norway since 1983 by the National Institute of Public Health. Uncomplicated AB0 and Rh(D) grouping, including Du typing, has been performed satisfactorily. Rh(D) grouping of presensitized, Rh (D) negative cells is still a problem, but one which has been reduced significantly. Both indirect and direct antiglobulin reactions have given about 15% false negative results, mainly with weak antibodies and weakly sensitized cells. Poor training of technicians in reading weak agglutination reactions may be an important source of error. The importance of post-graduate training of blood bank staff is emphasized.