Posted on 12/06/2017
Finding a compatible blood product for a patient transfusion isn’t always as simple as identifying their blood type. Depending upon the individual patient, it may take several days and involve Bonfils Blood Center’s Reference Laboratory, the only AABB* accredited immunohematology reference lab in Colorado and one of just 66 in the world which performs more complex testing than most hospital laboratories are equipped to handle.
When a patient goes to a hospital for a planned surgery or treatment and there is potential for a blood transfusion, their blood is drawn and it goes to the hospital laboratory. The laboratory tests the blood to determine their blood type, A, B, AB or O and to determine if the person has formed an antibody to red blood cells.
What is an antibody and how does a person develop one?
A human immune system is designed to act as an attack mechanism to defend the body from things like viruses and bacteria. Antibodies are made by white blood cells which are produced in the bone marrow. If a person is exposed to red blood cells (via pregnancy or transfusion) and those red blood cells vary slightly in structure from their own, it is possible that person will form an antibody directed to attack that foreign red cell structure or antigen. It is important that a laboratory can detect these antibodies because they can cause a transfusion reaction by destroying transfused red blood cells. Most transfusion reactions can be mild. However, in rare cases, they can be severe, or even deadly.
How common is it for a person to develop an antibody?
Only about 4 percent of the population will develop an antibody to a red cell antigen after transfusion. If a patient has previously received many units of blood, there is a higher chance that the person will have an antibody. In some cases, patients will form multiple antibodies and most hospitals do not have the resources and knowledge to identify the antibodies present. There are hundreds of antibodies a patient can develop. That’s when Bonfils Blood Center’s Reference Lab can help, concentrating on ruling out 23 of the most common clinically-significant ones.
How is a suitable blood product identified for a patient with an antibody?
When the antibody identification process is complete, reference lab technologists can choose compatible blood. For example, if a patient has a blood type of A-positive and has made an antibody to the E and S red cell antigens/structures, the technologist would choose A-positive red cells lacking E and S antigens. This blood would be compatible with the patient and safe to transfuse.
How are compatible donors found?
Bonfils continuously screens donors to maintain a database of donors whose blood meets specific patient needs. When donors who meet specific criteria give blood, their donation is specially tagged and sequestered in the Reference Lab to be used for specific patient needs. If the Reference Lab does not have a donation on hand that’s compatible with a specific patient, a compatible donor is then contacted and asked to give blood to help meet that individual patient’s need.
Who is qualified to work at Bonfils Reference Lab?
Bonfils’ Reference Lab tests samples from 255 hospitals around the region. On average, the lab will process 110 samples each month, about four per day. Testing can take anywhere from two hours to two days, depending on how many antibodies are present and their complexity.
Bonfils’ Reference Lab technologists have Medical Laboratory Science degrees and an American Society of Clinical Pathologists (ASCP) certification/license to perform the special tests needed to solve these complicated antibody identifications. Misidentifying or completely missing one or more red cell antibodies in a sample test could put a patient in grave danger. That’s why reference lab technologists generally train for approximately six months before they are deemed competent to work independently.
*AABB is a leader in setting standards for voluntary compliance in the fields of transfusion medicine and/or cellular therapies.