In which phenotype is there an absence of Rh antigens from the red cell membrane?

In which phenotype is there an absence of Rh antigens from the red cell membrane?

• A. Rh positive
• B. Rh null
• C. Du
• D. D negative

Answer: (B)

Rh antigens are part of a membrane protein complex on the red cell surface. In the Rh null phenotype, there are no detectable Rh antigens on the red cell membrane, meaning all Rh antigens (D, C, c, E, e) are absent. This distinguishes Rh null from the other options: Rh positive has the D antigen present; D negative lacks only the D antigen but usually retains other Rh antigens; Du is a partial D variant with some D epitopes missing but not completely absent.

Rh antigens are part of a membrane protein complex on the red cell surface. In the Rh null phenotype, there are no detectable Rh antigens on the red cell membrane, meaning all Rh antigens (D, C, c, E, e) are absent. This distinguishes Rh null from the other options: Rh positive has the D antigen present; D negative lacks only the D antigen but usually retains other Rh antigens; Du is a partial D variant with some D epitopes missing but not completely absent.