Unless you’ve recently given blood, you may not think much about your blood type.
The presence or absence of certain molecules called A or B antigens, as well as a protein called the Rh factor, determine which of the eight common blood types you have coursing through your veins. (Groups: A+, A-, B+, B-, AB+, AB-, O+ or O-.)
However, these antigens make a difference beyond just your blood, influencing other body systems like your blood vessels, nerve cells, and blood platelets—which is why your blood type may impact your risk of certain diseases.
