Feasibility and utility of a rapid ABO genotyping platform in transplantation and transfusion medicine

Serological ABO typing in transfusion medicine and organ transplantation, can face limitations in cases involving large volume transfusions, transplants, weak subgroups, or hematological malignancies. ABO genotyping can help resolve ABO type, and there is a need for a fast, reliable, and cost-effective testing approach.

We investigate a commercially available medium-throughput quantitative polymerase chain reaction (qPCR) ABO genotyping assay and evaluated routine samples from a tertiary academic transplant laboratory, samples previously ABO genotyped in the immunohematology and genomics reference laboratory, and samples showing discordant/mixed field reactivity in the hospital blood bank. Results were compared with serologic typing and Sanger sequencing, or next-generation sequencing (NGS) for some.

For routine transplant samples (n = 89), the qPCR assay demonstrated 100% concordance with serologic phenotypes and Sanger sequencing with one no-call result. For complex reference laboratory samples (n = 32), 91% concordance with serologic phenotype and 72% concordance with predicted phenotype and genotype by Sanger sequencing was achieved. qPCR identified variants encoding: A₁, A₂, A₃, and cisAB. In blood bank problem samples (n = 29), 79% were resolved by qPCR.

The qPCR assay's rapid turnaround time and automated interpretation make it particularly suitable for inclusion in the investigation and resolution of ABO serological typing problems. Its capabilities also align well with recent UNOS (United Network for Organ Sharing) guidance for deceased kidney donor ABO typing resolution and can potentially improve patient safety in transplantation settings, and aid in the evaluation of typing discrepancies in transfusion medicine practice.