A case of acute hemolytic transfusion reaction caused by anti-AnWj is reported in a patient with aplastic anemia requiring allogeneic stem cell transplantation. This is the second documented case of anti-AnWj to cause a hemolytic transfusion reaction. The case demonstrates the complexity of managing patients with rare antibodies and the importance of international collaboration in the management of these difficult cases.

Genotyping of patients with weak D serology led to an identified genotype in most patients. RhIG administration was avoided in 66% who were weak D Type 1, 2, or 3 or were D+. The use of a serologic algorithm to select patients for RHD genotyping identifies a majority of patients with weak D types not at risk for alloimmunization. This approach limits the number of genotyping investigations and the cost of providing classification for weak D types.

While implementation of new assays in commercial genotyping platforms to detect the polymorphisms reported here may not be justified given their apparent rarity, software interpretative algorithms may benefit from the identification of new alleles for a more accurate determination of genotypes and prediction of phenotypes.