Basic aspects, application and platforms currently available for molecular blood grouping of donor and patient population

Abstract

The majority of allelic variants conferring red cell blood group antigens are attributable to single nucleotide polymorphisms, which are immensely amenable to routine genotyping methods such as PCR‐RFLP, SSP, SSO and fluorescent‐based real‐time PCR assays. These techniques are feasible in a low‐ to medium‐throughput setting. Multiplexing and use of solid surfaces or beads for probe capture have further improved the throughput and turnaround time allowing multiple alleles to be interrogated simultaneously. Novel approaches, as in the use of MALDI‐TOF mass spectrometry, appear as an attractive option for accurate, cost‐effective, high‐throughput SNP genotyping within major blood centres. Massively parallel targeted sequencing is likely the next step in the evolution of RBC genotyping. In the hospital setting, genotyping is unlikely to supplant serological typing but would rather be complementary to it. Scenarios where it would play an important role would be in the transfusion management of transfusion dependant patients such as in sickle cell anaemia or in situations where RBC phenotyping cannot be reliably undertaken as in auto‐immune haemolytic anaemia and haemolytic disease of foetus and newborn. Genotyping would also be useful where anti‐sera are not readily available or are of weak potency. Molecular typing is likely to, however, show its greatest potential in donor genotyping to establish pools of fully typed donors as well as identify donors with rare blood groups. Such an exercise will facilitate prompt and efficient delivery of best‐matched blood for patients.

A multi‐centre study on the performance of the molecular genotyping platform ID RHD XT for resolving serological weak RhD phenotype in routine clinical practice

“…Some potentially immunogenic D variants such as DEL, partial D and some weak D types, which are very weakly expressed or only detectable by adsorption‐elution techniques, are frequently undetected by routine serological testing . In this regard, a considerable amount of literature has been published on the possible consequences arising from RhD typing errors.…”