Knowing your blood type is critical during emergency health situations. Knowing your blood type is crucial medical information, but unless you've given blood before you might not be sure what yours is ...

There are different blood types: A, B, AB, and O, with each also being Rh-positive or Rh-negative. Knowing your blood type is important for safe blood transfusions and organ transplants. Type ...

A person's blood type is determined by "the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body," according to American Red Cross.