D antigen
Definition
The most immunogenic Rh antigen, encoded by the RHD gene. Its presence defines Rh-positive; its absence defines Rh-negative. No naturally occurring anti-D exists; the antibody develops only after exposure to D-positive cells through transfusion or pregnancy.
Related terms
- CDE nomenclature (Fisher-Race)
- The modern standard notation for Rh antigens, naming three antithetical pairs: C/c, D (no d), and E/e. Haplotypes such as CDe (R1),...
- Indirect antiglobulin test (IAT)
- A two-stage serological test in which IgG antibody is incubated with red cells, unbound antibody is washed away, and anti-human globulin (Coombs...
- Rh-Hr nomenclature (Wiener)
- An earlier notation system using alphanumeric agglutinogen codes (R0, R1, R2, Rz, r, r', r'', ry) for Rh haplotypes. Wiener's R1 corresponds...
- RHD genotyping
- PCR-based molecular typing of the RHD gene to determine D antigen status from DNA, including from dried biological evidence where serological red...
- Weak D (formerly Du)
- A reduced-expression variant of the D antigen that does not agglutinate red cells with standard IgM anti-D reagent in the direct test...
Explained in
- The Rh Blood Group System in Forensic ContextThe most immunogenic Rh antigen, encoded by the RHD gene. Its presence defines Rh-positive; its absence defines Rh-negative. No naturally occurring anti-D exis...