Report of the Second International Workshop on molecular blood group genotyping.

The second International Society of Blood Transfusion and International Council for Standardization in Haematology workshop on molecular blood group genotyping was held in 2006. Forty-one laboratories participated. Six samples were distributed: two representing DNA from transfusion-dependent patients for testing for all clinically important polymorphisms; two representing DNA from amniotic fluid for RhD, Rhc, and K testing; and two plasma samples from RhD-negative pregnant women for fetal RhD testing (only tested by 20 laboratories). Overall, a high level of accuracy was achieved by most of the laboratories, although the error rate caused by RHDPsi was not acceptable and needs to be addressed. With greater care and attention to detail, very high standards could be set for molecular blood group genotyping.