Report of the third international workshop on molecular blood group genotyping.

The Third International Society of Blood Transfusion Workshop on Molecular Blood Group Genotyping was held in 2008, with a feedback meeting at the International Society of Blood Transfusion Congress in Macao SAR, China. Thirty-three laboratories participated, eight less than in 2006. Six samples were distributed: sample 1 representing DNA from a sample referred because of abnormal serological results in D testing; samples 2 and 3 from transfusion-dependent patients for testing for all clinically important polymorphisms; sample 4 a mixture of two DNA samples designed to simulate a chimera, referred because of abnormal serological results in donor testing; and samples 5 and 6 plasma samples from RhD-negative pregnant women, for fetal RhD testing (only tested by 17 laboratories). For samples 1-3, 24 of 33 laboratories obtained completely correct results. For sample 4, the ability to detect the minority DNA population was partly dependent on method. Of the 17 laboratories that received samples 5 and 6, 13 reported correct results on both samples. Overall a small improvement from previous workshops was noted, but there is still room for improvement. The main conclusion for the 2006 workshop can be reiterated: with greater care and attention to detail, very high standards could be set for molecular blood group genotyping.