The antigen found in red blood cells that is used in blood typing is the which?

The antigen found in red blood cells that is used in blood typing is the which?

• A. Rh factor
• B. ABO antigen
• C. Agglutinogen
• D. H antigen

Answer: (A)

Blood typing depends on antigens on the surface of red blood cells. The Rh factor, also known as the D antigen, is a key marker used to classify blood as positive or negative. If the D antigen is present, the blood is Rh-positive; if it's absent, the blood is Rh-negative. This determination is routinely done alongside ABO typing because matching Rh status is essential for safe transfusions and pregnancy outcomes. The ABO antigens (A and B) define the main type, but the Rh factor specifically refers to the antigen used to label positive or negative status, making it the best answer in this context. The H antigen is a precursor to ABO antigens and not the primary marker used for routine blood typing, and agglutinogen is a general term for an antigen causing agglutination, not a specific blood-type marker.

Blood typing depends on antigens on the surface of red blood cells. The Rh factor, also known as the D antigen, is a key marker used to classify blood as positive or negative. If the D antigen is present, the blood is Rh-positive; if it's absent, the blood is Rh-negative. This determination is routinely done alongside ABO typing because matching Rh status is essential for safe transfusions and pregnancy outcomes. The ABO antigens (A and B) define the main type, but the Rh factor specifically refers to the antigen used to label positive or negative status, making it the best answer in this context. The H antigen is a precursor to ABO antigens and not the primary marker used for routine blood typing, and agglutinogen is a general term for an antigen causing agglutination, not a specific blood-type marker.