But what determines blood type and what does that blood type mean? Blood types are determined by antigens -- a substance ... the blood sample is mixed with antibodies against type A and B blood.

A person with an A blood type has the A antigen on the blood cells and the B antibody in the plasma. Whether you have a positive or negative blood type (like A+) depends on whether you have an ...

The new test, on the other hand, uses a paper strip that is coated in antibodies that recognize antigens found in different blood types, plus a commonly used green dye. When a drop of blood is put on ...