Question

How many blood types exist including the positive and negative factors?

(a) 3

(b) 4

(c) 8

(d) 6

I have been asked this question in exam.

This interesting question is from Blood Groups in section Pathology of Clinical Science

Answer 1

The correct answer is (c) 8

To explain I would say: Blood is classified into two factors, antigen-antibody and rhesus factor. There are two types of antigens A and B. The cells having antigen A have antibody B while those having antigen B have antibody A. This makes the blood group A and B. AB blood group have both antigens A and B and no antibodies. Blood group has no antigens but antibodies for both. This makes four blood groups A, B, AB, O. The presence and absence of Rh factor make these four blood groups into 8. A+, A-, B+, B-, AB+, AB-, O+ and O-.