AEMCA Practice Exam

What are the four primary blood groups?

1. A, B, O, AB

2. AB, A, B, O

3. A, B, AB, O+

4. A+, B-, AB+, O-

The correct answer is: AB, A, B, O

The four primary blood groups are categorized based on the presence or absence of specific antigens on the surface of red blood cells. The correct identification of these groups is essential for blood transfusions and other medical procedures. The primary blood groups are A, B, AB, and O. This classification is based on the ABO blood group system, where: - Group A has A antigens. - Group B has B antigens. - Group AB has both A and B antigens. - Group O has neither A nor B antigens. Choosing the sequence AB, A, B, O showcases all four blood groups without any additional notations, such as a "+" or "-", which represent the Rh factor or blood type variation. This recognition is important, as the basic ABO system is referred to before considering Rh compatibility, which further classifies blood into positive or negative types. The other options include either additional details that are not part of the primary groups or an incorrect sequence. The emphasis on AB, A, B, O in the correct answer effectively summarizes the essential classification of blood types.