Daily Trivia Answer

Question:: What is the rarest blood type: A, B, or AB?

Answer:: AB-
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(from American Red Cross)

The ABO Blood Group System
There are four major blood groups determined by the presence or absence of two antigens – A and B – on the surface of red blood cells:

• Group A – has only the A antigen on red cells (and B antibody in the plasma) 
• Group B – has only the B antigen on red cells (and A antibody in the plasma) 
• Group AB – has both A and B antigens on red cells (but neither A nor B antibody in the plasma)
• Group O – has neither A nor B antigens on red cells (but both A and B antibody are in the plasma)

Blood Types and the Population

O positive is the most common blood type. Not all ethnic groups have the same mix of these blood types. Hispanic people, for example, have a relatively high number of O’s, while Asian people have a relatively high number of B’s. The mix of the different blood types in the U.S. population is:

	Caucasians	African American	Hispanic	Asian
O +	37%	47%	53%	39%
O -	8%	4%	4%	1%
A +	33%	24%	29%	27%
A -	7%	2%	2%	0.5%
B +	9%	18%	9%	25%
B -	2%	1%	1%	0.4%
AB +	3%	4%	2%	7%
AB -	1%	0.3%	0.2%	0.1%