A simple approach to confirm the presence of anti-D in sera with presumed anti-D+C specificity.

The G antigen belongs to the Rh system and is present on most D-positive red blood cells (RBC) and on most C-positive RBC1. For this reason, the true specificity of serum that apparently has anti-D and anti-C specificity when tested with the usual panels for the identification of irregular antibodies could correspond to one of the five possible combinations: anti-D and anti-C (D+C), anti-D and anti-G (D+G), anti-D and anti-C and anti-G (D+C+G), anti-C and anti-G (C+G), and anti-G2. The correct identification of the specificity and, in particular, the determination of whether anti-D is present or not are of paramount clinical importance in different clinical settings. In pregnant women, the presence of anti-D excludes the need for the administration of prophylactic anti-D immunoglobulin (RhIG). In addition, the exclusion of the presence of anti-D in samples from D-negative women with D-negative partners or from D-negative recipients of D-negative blood components can avoid potential social or medico-legal complications2. We describe here a simple approach that enables us to determine whether anti-D is present or not in serum presumed to contain anti-D and anti-C specificity. This protocol was employed in the study of 32 samples with presumed anti-D+C specificity confirming the utility of this simple and less time-consuming strategy.