Evaluation of kodecytes using function‐spacer‐lipid constructs as a survey material for external proficiency testing for ABO subgrouping

Background It is not easy to find natural red blood cells ( RBC s) with weak A (A w ) or weak B phenotype (B w ) for use as quality controls in ABO subgroup testing (subgrouping). The aim of this study was to prepare RBC kodecytes with synthetic blood group A and/or B function‐spacer‐lipid ( FSL ) constructs and to evaluate the possibility of using such kodecytes as a survey material for an external proficiency test ( PT ) to improve the quality of subgroup analysis. Methods Three types of survey samples, including O phenotype RBC s and A kodecytes with A w (0.02 mg/mL FSL ‐A solution) and B kodecytes with B w (0.15 mg/mL FSL ‐B solution) were sent to 53 laboratories for an educational trial of PT for subgrouping. Cell typing was done using the manual tube technique. Results Forty‐three laboratories responded, and the re‐activities of the survey samples varied from 0 to 4+ against anti‐A and anti‐B monoclonal reagents(MoAbs). Twenty‐nine laboratories (67%) correctly grouped the B w kodecytes as B w . Fifteen (35%), 21 (48%), and 6 (13%) laboratories grouped the A w kodecytes as A w , A 2 , and O phenotypes, respectively. The anti‐A MoAb clone affects the results of cell typing for A w kodecytes. The stability of kodecytes was similar to that of natural O RBC s during storage. Conclusion Our kodecytes were useful as a survey material, and the survey results showed the necessity of materials for PT for subgrouping to improve the quality of laboratory analysis regardless of the different reactions according to the MoAb.