ABO Genotyping: From PCR-Based Assays to Long-Read Sequencing
10.17945/kjbt.2026.37.1.1
- Author:
Junhyup SONG
1
;
Soon Sung KWON
;
Sinyoung KIM
Author Information
1. Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea
- Publication Type:Review Article
- From:Korean Journal of Blood Transfusion
2026;37(1):1-13
- CountryRepublic of Korea
- Language:English
-
Abstract:
ABO genotyping was first attempted shortly after the ABO gene was identified in 1990, when PCR-based assays, including PCR-RFLP (restriction fragment length polymorphism), PCR-SSCP (single strand conformation polymorphism), and PCR-SSP (sequence-specific primer), enabled discrimination among the major alleles (A, B, and O).Because various point mutations in exons 6 and 7 underlying subgroup phenotypes were progressively elucidated, these variants also became the targets for genotyping assays. Nevertheless, PCR-based approaches are inherently limited to the detection of predefined variants and require additional allelic separation and direct sequencing to identify alleles corresponding to subgroup phenotypes. Since the 2010s, next-generation sequencing (NGS) has enabled comprehensive analysis of the genetic variation across the entire ABO gene through massively parallel sequencing, helping identify several novel alleles at the population level. On the other hand, its short-read architecture imposes limitations in haplotype phasing. Long-read sequencing technologies have recently been introduced to overcome these limitations and are increasingly being applied, allowing direct analysis of full-length haplotypes and offering advantages in detecting recombination events and characterizing repetitive regions. Although advances in molecular genetics have substantially improved the accuracy and convenience of genotyping methods, their clinical application remains limited.The advantages of serological testing—namely, accessibility, accuracy, and low cost—continue to support its primary role in routine practice. Although ABO genotyping cannot yet replace serological methods, it serves as a valuable complementary tool in resolving discrepant cases and in specialized settings such as organ transplantation. Its clinical utility is expected to expand further as technological advances continue.
