Which statement defines Rh-positive status?

Which statement defines Rh-positive status?

• A. The D antigen is present in Rh positive individuals
• B. The D antigen is absent in Rh positive individuals
• C. Rh status is independent of D antigen
• D. Rh status is determined by ABO type

Answer: (A)

Rh-positive status means the D antigen is present on red blood cells. The defining feature of the Rh blood group system is the presence or absence of the D antigen on the surface of RBCs. If the D antigen is present, the individual is considered Rh-positive; if it is absent, the individual is Rh-negative. The other statements are not correct because Rh status is specifically tied to the D antigen, not to its absence in positives, not to independence from D, and not determined by ABO type, which is a separate blood group system. In practice, serology uses anti-D antibodies to detect the D antigen: if the RBCs agglutinate, they’re Rh-positive; if not, Rh-negative.

Rh-positive status means the D antigen is present on red blood cells. The defining feature of the Rh blood group system is the presence or absence of the D antigen on the surface of RBCs. If the D antigen is present, the individual is considered Rh-positive; if it is absent, the individual is Rh-negative. The other statements are not correct because Rh status is specifically tied to the D antigen, not to its absence in positives, not to independence from D, and not determined by ABO type, which is a separate blood group system. In practice, serology uses anti-D antibodies to detect the D antigen: if the RBCs agglutinate, they’re Rh-positive; if not, Rh-negative.