The Expanding Frontier of Molecular Immunohematology: new blood groups, new antigens, and evolving testing strategies

Molecular testing platforms are well-established in today’s immunohematology practice and are used to provide an extended predicted red cell phenotype for patients and donors. Molecular testing offers distinct advantages over traditional serologic typing: It can provide a valid red cell phenotype in recently transfused patients, detect partial and weak antigen variants, and address antigens for which commercial serologic reagents are not available. Furthermore, molecular assays can interrogate multiple antigens at a time – and often multiple samples at a time – at the same time in a single assay run.

Serology and molecular testing should be viewed as complementary approaches in immunohematology, and all molecularly predicted phenotype results should be reconciled with available serologic findings and alloimmunization history. These results are all pieces of the same puzzle and should fit together logically. If any discrepancies arise among these testing modalities, please contact our immunohematology reference laboratory for further consultation, and we will help coordinate additional specialized testing if needed.

Molecular methods, particularly Next Generation Sequencing (NGS), have significantly expanded our immunohematology knowledge. This year, a new blood group, JAMA, was approved by the International Society of Blood Transfusion as blood group 49. In addition, two new red cell antigens were approved and added to the list: DINT in the Diego blood group system, and LUIWIN in the Lutheran system. Posters and presentations at this year’s ISBT annual meeting also reported a total of 12 novel alleles across 9 known blood groups. The latest molecular immunohematology information can be accessed through the new Blood Group Database, openly available at https://blooddatabase.isbtweb.org.

This rapid rate of discovery has been made possible by the application of genomics technologies in our field. Over the past decade, literature has shown the strength of NGS in delivering highly precise, comprehensive blood group profiles with exceptional throughput. Please stay tuned as the Carter BloodCare Genomics Testing program continues to expand in the near future.