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, 45 (1), 5-10

ABO Mistyping of cis-AB Blood Group by the Automated Microplate Technique


ABO Mistyping of cis-AB Blood Group by the Automated Microplate Technique

Sejong Chun et al. Transfus Med Hemother.


Background: The cis-AB phenotype, although rare, is the relatively most frequent of ABO subgroups in Koreans. To prevent ABO mistyping of cis-AB samples, our hospital has applied a combination of the manual tile method with automated devices. Herein, we report cases of ABO mistyping detected by the combination testing system.

Methods: Cases that showed discrepant results by automated devices and the manual tile method were evaluated. These samples were also tested by the standard tube method. The automated devices used in this study were a QWALYS-3 and Galileo NEO. Exons 6 and 7 of the ABO gene were sequenced.

Results: 13 cases that had the cis-AB allele showed results suggestive of the cis-AB subgroup by manual methods, but were interpreted as AB by either automated device. This happened in 87.5% of these cases by QWALYS-3 and 70.0% by Galileo NEO. Genotyping results showed that 12 cases were ABO*cis-AB01/ABO*O01 or ABO*cis-AB01/ABO*O02, and one case was ABO*cis-AB01/ ABO*A102.

Conclusion: Cis-AB samples were mistyped as AB by the automated microplate technique in some cases. We suggest that the manual tile method can be a simple supplemental test for the detection of the cis-AB phenotype, especially in countries with relatively high cis-AB prevalence.

Keywords: ABO; Automation; Microplate technique; Mistyping; cis-AB.


Fig. 1
Fig. 1
Example of manual tile testing results of cell typing of (1) cis-AB, (2) typical AB and (3) O type blood. All samples were RhD-positive. Results for anti-B sera of cis-AB represents weakly reactive, AB represents strongly reactive and O represents negative results.
Fig. 2
Fig. 2
The outline of the work process to identify cis-AB samples with discrepancies between the automated and manual serological methods. *Only cell typing was done with tile methods. **Anti-A1 was applied to the manual tube method.

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