Wolf D. Kuhlmann
The Rh blood group is a polymorphic system with significant issues in blood transfusion. This holds especially true for Rhesus D antigen. Serologic RhD typing can be tricky because monoclonal anti-D reagents may react with weak and partial D types in a variable manner. In a case of pregnancy with later proven RHD*10 (DAU) and categorized as partial D, we were close on false RhD phenotyping because all serologic tests resulted in full strength reaction with several different anti-D reagents in different standard tests. At no time, agglutination signs for a weak or partial D variant were observed. The DAU cluster and other RHD variants are not prevailing in Europeans. However, D-variants may become more frequent with migration and the possibility of false serologic results in D antigen typing has to be regarded. Potentially, molecular RHD analysis will become increasingly required to ascertain the correct RhD status.