Korean J Blood Transfus.  2023 Apr;34(1):12-20. 10.17945/kjbt.2023.34.1.1 2.

Clinical Application of ABO Genotyping: 5-Year Experience from a Single Tertiary Care Center in Korea

• Lee HW
• Jeong IH
• Seo JY
• Jang JH
• Cho D

• KMID: 2541995
• DOI: http://doi.org/10.17945/kjbt.2023.34.1.1 2

Abstract

Background
ABO genotyping is performed when the exact ABO blood type cannot be determined through serological testing. Conventionally, only exons 6 and 7 of the ABO gene have been analyzed, but our laboratory introduced additional analysis of the proximal promoter and intron 1 ＋5.8 kb site. Accordingly, we report the clinical use of ABO genotyping and distribution of the ABO subgroups based on our experience over the past 5 years.
Methods
A total of 265 samples tested at the Samsung Medical Center from August 2017 to July 2022 were retrospectively analyzed at their request. Serological ABO blood typing and direct sequencing of exons 6 and 7 were performed on all samples, and additional analysis of the regulatory region of the ABO gene was performed on 17 samples. Since some of the ABO discrepant cases revealed multiple causes, a total of 339 causes among 238 ABO discrepant cases were analyzed.
Results
Among the total of 265 samples, 89.8% (238/265) exhibited ABO discrepancies. Weak red cell reactivity (51.6%, 175/339) was the most common cause of ABO discrepancy, followed by extra serum reactivity (35.7%, 121/339). Among the samples, 40.8% (108/265) were identified as ABO subgroups. Among the 108 ABO subgroup alleles, cisAB.01 in exons 6 and 7 accounted for 82 cases (75.9%, 82/108), and two g.10925C＞T mutations in intron 1 ＋5.8 kb were identified.
Conclusion
Through our recent experience of the last 5 years of ABO genotyping, we elucidated the cause of ABO discrepancies and ABO subgroup alleles. The extended sequencing of the regulatory region of the ABO gene was helpful for further understanding the ABO discrepancy caused by weak red cell reactivity. (Korean J Blood Transfus 2023;34:12-20)

Keyword

ABO blood type; Genotyping; ABO discrepancy; ABO subgroup