Why is performing a crossmatch important before a blood transfusion?

Performing a crossmatch before a blood transfusion is essential for matching the donor and recipient blood for compatibility. The crossmatch process involves mixing a sample of the recipient's blood with the donor's blood to observe for any adverse reactions, such as agglutination. This is crucial because incompatible blood transfusions can lead to serious and potentially fatal reactions in patients, including hemolytic transfusion reactions, where the recipient's immune system attacks the transfused red blood cells.

While confirming the patient's blood type is an important part of the transfusion process, it is not sufficient on its own to ensure safety. Evaluating the blood for hemoglobin levels is also important, but it does not relate directly to ensuring compatibility between donor and recipient. Ensuring donor blood is free of pathogens is a separate aspect of blood safety that addresses infectious disease transmission but does not evaluate compatibility specifically. Thus, the primary purpose of conducting a crossmatch is to ensure that the donor's blood is compatible with the recipient's blood type, preventing immune reactions during the transfusion.