What is the purpose of typing and crossmatch prior to a blood transfusion?

The purpose of typing and crossmatch prior to a blood transfusion is to determine blood types and antigens. This process is crucial for ensuring compatibility between the donor's blood and the recipient's blood. When blood is transfused, it is vital that the two blood types match; otherwise, the recipient’s immune system may recognize the transfused blood as foreign and mount an immune response against it.

Typing refers to identifying the specific blood group (such as A, B, AB, or O) and the Rh factor present on the surface of red blood cells. Crossmatching involves mixing a small sample of the recipient's blood with the donor's blood to check for any adverse reactions, confirming that the recipient will not have an immune reaction to the transfused blood. This thorough verification process helps prevent potentially life-threatening complications that can arise from incompatible blood transfusions.

The other choices do not relate to the blood transfusion process; for example, assessing oxygen levels and evaluating blood sugar levels focus on different physiological aspects, while measuring blood pressure pertains to cardiovascular monitoring rather than blood compatibility.