The UK National External Quality Assessment Scheme in Blood Group Serology, Compatibility testing 1979-1980.

Seven proficiency tests in compatibility testing were issued in 1979 to 1980. In each exercise participants were required to test five sera, most of which contained alloantibodies, against three samples of red cells by three designated techniques, namely agglutination in saline at room temperature, agglutination in albumin at 37 degrees C and the antiglobulin test at 37 degrees C. Comparability was achieved by scoring of results. Incompatibilities were missed by 3.5 to 22% of participants in five exercises in which undiluted antibodies were issued. There was no significant improvement in performance over two years. Antibodies which were issued diluted, but detectable by antiglobulin test, were missed with high frequency.