A new RHD testing process: combining serological weak D confirmation testing and genotyping

The aim of the study is to establish a rapid, effective, and cost-efficient strategy for identifying RhD-negative (D−) blood types in China. Among the 125 samples analyzed, D− samples accounted for 76.0% (95/125), of which 70 cases (73.7%) were ccee, all characterized as RHD*01N.01/RHD*01N.01, while 25 cases (26.3%) were non-ccee, including 15 RHD*01N.01/RHD*01N.01 and 10 RHD–RHCE hybrid variants. Samples that were positive in weak D confirmation testing represented 24.0% (30/125). Since confirmation testing did not show significant diagnostic efficacy for RHD*01EL.01, RHD molecular analysis appeared to be a more accurate detection method. Based on molecular findings, the paper recommends using only five genotyping targets for simple RHD genotyping: RHD exons 1, 5, and 10, and the 845G>A and 1227G>A variants, which effectively detected most samples (29/30; 96.7%). In conclusion, this study recommends performing weak D confirmation testing alongside routine RhD typing for negative samples, thereby eliminating the need for further molecular analysis in over 70% of cases and conserving time and laboratory resources. For samples that test positive in weak D confirmation, simple RHD genotyping effectively identifies Asian-type DEL variants, RHD*15, and RHD–RHCE hybrid alleles, while follow-up molecular analysis facilitates cost-efficient detection of other rare RHD variants.