A colleague in the United States wonders if colleagues affiliated with the UK National Blood Service would inform the e-Network Forum if ABO, Rh, and/or K typing is routinely being performed by phenotyping or genotyping at this point in time.

The following comments have been received.

ADDENDA May 31, 2006

1. A colleague affiliated with the English National Blood Services (NBS) reports that they undertake testing on about 1.8M donations, 330,000 antenatal screening samples and about 50,000 referred samples from hospitals (alloantibody investigations in hospital patients or antenatal women etc) annually. Within the English NBS, all new blood donors get ABO, D, C, c, E, e, K phenotypes and some get additional phenotyping (eg Jk(a) and Fy(a)). All repeat donations get ABO and D. Under UK regulations, before a donation can be labelled with any phenotype, it must be tested twice, one of which must be on the current donation (i.e., one could be historical). Genotyping is not currently undertaken on donations except when looking for phenotypes where reagents are in short supply (eg, Dombrock). All of the antenatal screening samples that they test get tested for ABO and D phenotype. All of the referred samples from hospitals get tested for ABO, D, C, c, E, e, K phenotypes, as well as additional phenotypes if an antibody is suspected or identified. Occasionally, when the patient is transfused, has a strong DAT, or has an unusual alloantibody, the patient will be tested for their genotype for several blood group polymorphisms. When a pregnant woman has a clinically significant antibody above a certain titer, it may be recommended to genotype her fetus for the relevant polymorphism, using maternal plasma in a quantitative PCR method. The responding NBS colleague concludes by saying that the English NBS is separate from the Blood Services in Scotland, Wales and Northern Ireland. While all these organizations work to the same basic requirements, testing policy may vary in detail.

2. A colleague from Scotland reports that as far as he knows, the UK still relies on phenotyping (rather than genotyping) for routine ABO, Rh and K typing. This is "certainly true in Scotland. Genotyping is used, but not for the routine service".

3. The Head of Molecular Diagnostics at the International Blood Group Reference Laboratory in Bristol reports that ABO, Rh, and K typing are performed routinely by serological means in the UK, that is, by phenotyping. Molecular methods (genotyping) are only used in the UK when a suitable red cell sample is not available; e.g., for fetal typing and in multi-transfused patients. This very rarely applies to ABO, and ABO molecular genotyping is very seldom carried out.

Please submit comments to the e-Network Forum.

Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator