Original Article

Korean J Lab Med 2006; 26(2): 107-113

Published online April 1, 2006

Copyright © Korean Society for Laboratory Medicine.

Resolution of ABO Discrepancies by ABO Genotyping

Duck Cho, M.D.1, Jin-Sol Lee, M.D.1, Ji-Young Park, M.D.1, Mi-Jeong Jeon, M.D.2, Jeong-Won Song, Ph.D.1, Soo-Hyun Kim, M.D.3,Myung-Geun Shin, M.D.1, Jong-Hee Shin, M.D.1, Soon-Pal Suh, M.D.1, and Dong Wook Ryang, M.D.1

Department of Laboratory Medicine, Chonnam National University Medical School1, Gwangju; Gwangju-Chonnam Red Cross Blood Center2, Gwangju; Department of Laboratory Medicine, Colleage of Medicine, Seonam University Medical School3, Namwon, Korea

Correspondence to: 양동욱
우 501-757 광주광역시 동구 학1동 8 전남대학교병원 진단검사의학과
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*본 논문은 2003년도 전남대학교 학술연구비 지원에 의하여 연구되었음.


Background : Before a blood transfusion, both red cell and serum typing need to be matched for ABO tests on the donor and patient (recipient). When a mismatch exists in the tests, additional ABO genotyping and serological tests are required for the resolution of the discrepancy. We performed ABO genotyping on a series of blood donors and patients with ABO discrepancies to assist in resolving their blood groups.
Methods : We examined 46 samples with ABO discrepancies from a random pool of donors recruited at Gwangju-Chonnam Red Cross Blood Center and from patients at Chonnam National University Hospital between May 2004 and July 2005. ABO genotyping was performed on all samples with an allele specific polymerase chain reaction for differentiation of A, B,O, cis-AB, Avar (784 G>A), and B var (547 G>A) alleles; routine serologic tests were also performed. Exon 6 and 7 of ABO gene from five samples were sequenced.
Results : The genotypes of 18 donors/patients with weakened A or B antigen expressions consisted of 4 cases of cis-AB/O (3 A2B3, 1 A2B); 5 cases of cis-AB/A (5 A1Bx or el); 2 cases of A/O (1 O, 1 Am or x); 1 case of B/O (1 Bm or x); 4 cases of A/B (1 A2B , 1 A1Bx or el, 2 A1B3); and 2 cases of Avar/B (2 AwB). On the other hand, the genotypes of 28 samples with unexpected serum reactions included 18 cases of A/O (16 A1, 2 Aint); 7 cases of A/A (5 A1, 1 A1Bx or el, 1 A1Bw); and 3 cases of O/O (1 O, 2 Bw).
Conclusions : ABO genotyping is useful for differentiating the ABO discrepancies that were difficult to resolve by serological tests. The most frequent unusual red cell reactions were weak A and B antigen expressions, which were resulted from the ABO subgroup alleles including cis-AB allele, whereas the most frequent unusual serum reactions were caused by decreased anti-B titers.

Keywords: ABO, Genotyping, Discrepancy