What type of sample is required for blood bank crossmatching?

For blood bank crossmatching, a serum specimen is required. This is because crossmatching involves testing the compatibility of the donor's blood with the recipient's blood to ensure that there are no adverse reactions during a transfusion. Serum, which is the liquid part of the blood that remains after clotting has occurred, contains antibodies that can react with specific antigens on red blood cells.

In this process, the serum from the recipient is tested against the red blood cells from the donor to check for any potential immunological reactions. This ensures the safety and efficacy of the transfusion. The presence of specific antibodies in the serum can indicate whether the blood types are compatible, which is crucial for successful transfusions to prevent hemolytic reactions.

Other types of samples, such as plasma or whole blood, may not provide the same type of antibody information needed for this crucial test, and capillary blood specimens are not typically used in crossmatching due to the volume and composition required for accurate testing.