Which of the following Rh antigens has the highest frequency in Caucasians?

The Rh antigen with the highest frequency in Caucasians is the antigen referred to as "e." The Rh blood group system is one of the major blood group systems in humans, and it is composed of several antigens, including D, C, c, E, and e. Among these, the antigen e is found in a significant majority of the Caucasian population, often cited as being present in approximately 98% of individuals.

Understanding the prevalence of the different Rh antigens is crucial for blood transfusion and pregnancy management. The D antigen is also common but tends to have a slightly lower frequency compared to e in Caucasian populations. Antigens C and E have lower frequencies than both D and e, and the c antigen has a higher prevalence in certain other ethnic groups but does not surpass the frequency of e in Caucasians.

This knowledge helps transfusion specialists and healthcare professionals ensure compatibility in blood transfusions and manage Rh incompatibility in pregnancy more effectively.