What is the purpose of crossmatching blood?

The purpose of crossmatching blood is primarily to ensure compatibility between the donor's and recipient's blood. This crucial step in the blood transfusion process involves mixing a small sample of the donor's blood with the recipient's blood to observe for any adverse reactions. If the blood types are incompatible, the recipient's immune system may attack the foreign blood cells, leading to serious health risks, including hemolytic transfusion reactions. Thus, confirming compatibility through crossmatching helps to safeguard the recipient’s health during a transfusion.

Testing for infectious diseases, while a vital aspect of blood safety, is not the primary focus of crossmatching. It serves a different purpose and is performed separately to screen for pathogens in the donated blood. Enhancing blood clotting factors and increasing blood storage time are also essential but are not related to the compatibility checking process that crossmatching is designed to accomplish.