Prevalence and distribution of serological characteristics of weak ABO subgroups in the Chinese population.

Objectives: This study aimed to determine the true frequency of weak ABO subgroups and to investigate the serological characteristics of various subgroup alleles in the Chinese population.

Methods: A total of 2,945,643 blood samples were collected from January 2009 to December 2017. After initial screening and re-examination using automatic blood group analyzers, all ABO-discrepant samples were confirmed by standard serological analysis and molecular detection by DNA sequencing.