Before blood transfusion
Learn about what happens before the blood transfusion.
Last updated 13 March 2026
Before blood transfusion
Both the donor's blood and yours will need to be tested before the blood transfusion process begins.
Screening of blood
A blood sample will be taken to confirm your blood group and to screen for unusual protein. This unusual protein may react against certain red cells in the blood you will receive during the transfusion. More blood samples may be needed to identify this protein if the screening is positive. You may therefore have to wait for some time for these tests to be completed, but they are necessary to ensure your safety.
Cross-matching
Before the red cell transfusion is carried out, the donor's blood is tested against your own blood sample (called cross-matching) to ensure that the red cells to be transfused are compatible with your blood.
Verifying your identity
Before the transfusion starts, your identity will be carefully checked against the identity written on the unit of assigned blood.