What Happens During Blood Transfusion

Despite the advances made in the processes of identifying blood groups in humans, blood transfusion is still considered a potentially risky procedure and is recommended only when patients have no other options. This is to avoid transfusion-transmitted infections and acute hemolytic reactions.

Hospitals in Singapore have guidelines when it comes to donating and receiving blood components, which include red cells, platelets, granulocytes, cryoprecipitate, and fresh frozen plasma.

Matching Process and Compatibility

Before blood transfusion can occur, blood typing is performed for every donated blood bag. The results will make it easier to find stocks of blood bags for individuals who will need a blood transfusion in the future. There are eight blood types based on the combination of ABO and Rh antigens, such as; A positive, B positive, A negative, B negative, AB positive, AB negative, O positive, and O negative.

There are different guidelines for transfusion of plasma, cryoprecipitate, and platelets than those set for red blood cells transfusion. The same can be said for organ, tissue, and bone marrow donation, too. All of the donor samples are tested first for compatibility with the receiver to avoid reactions.

Antibody Screening

Once the blood typing is done, antibody screening is performed to determine if the receiver’s plasma has other antibodies present besides those already tested for A, B, and Rh. This means that there is still a possibility that the donor will not be compatible with the receiver even when the first test is completed. For red blood cells transfusion, there is also another test that should be performed called cross-matching after the antibody screening.

In this process, the donor’s red cells are mixed with the plasma of the receiver to observe the reaction. Cross-matching, however, is no longer needed for plasma and platelets transfusions.

Blood Transfusion

Once the doctors are satisfied with the results of the tests, blood transfusion is recommended. Red blood cells transfusion is monitored by a hospital staff to see if the receiver exhibits any reaction by checking the blood pressure, heart rate, and temperature. The process is usually completed within 4 hours, while each bag is given after every few hours.

Blood transfusion reactions nowadays are rare although they still pose a risk, but the more common problems come from infections from the donated blood. Individuals who experience the following symptoms within the next few days after the transfusion should contact the hospital right away: headache, itching, body pain, nausea and dizziness, difficulty breathing, and shivering.

Transfusion reactions include allergies, febrile reaction, lung injury, hemolytic reaction, and graft-versus-host disease. Possible infections to watch out for are bacterial contamination, hepatitis B, hepatitis C, human immunodeficiency virus, cytomegalovirus, other STDs, and other infections.

03 Feb 2020