Since the description of the RhD antigen by Levine and Stetson in 1939, more than 40 other Rh antigen complexes have been identified. With the exception of the C, c, E and e and perhaps C^w, few of these antigens or their corresponding antibodies are controlled by a series of closely linked loci on chromosome 1, the genetic contribution from each parent being inherited as a haplotype e.g. Cde, cDE etc. Used separately, anti-Rh blood grouping reagents will indicate whether an individual expresses the corresponding antigen – an essential procedure in the determination of antibody specificity and selection of blood for transfusion of patients with Rh antibodies.

The Biorex Diagnostics Anti-C reagent is for the in vitro detection and identification of the human C blood group antigen by direct agglutination.