You may have heard discussions about “matching” and kidney transplantation. There are actually three tests that are done to evaluate donors. They are blood type, crossmatch, and HLA testing. This blood test is the first step in the process of living donation and determines if you are compatible or a “match” to your recipient.
Blood Typing
There are 4 different blood types. The most common blood type in the population is type O. The next most common is blood type A, then B, and the rarest is blood type AB. The blood type of the donor must be compatible with the recipient. The rules for blood type in transplantation are the same as they are for blood transfusion. Some blood types can give to others and some may not. Blood type O is considered the universal donor. People with blood type O can give to any other blood type. Blood type AB is called the universal recipient because they can receive an organ or blood from people with any blood type. The chart below shows which blood type can donate to which.
| If your blood type is: | You can donate to these blood types: |
| TYPE O | TYPE O, A, B, AB |
| TYPE A | TYPE A, AB |
| TYPE B | TYPE B, AB |
| TYPE AB | TYPE AB |
HLA Typing
HLA typing is also called “tissue typing”. HLA stands for human leukocyte antigen. Antigens are proteins on the cells in the body. Out of over 100 different antigens that have been identified, there are six that have been shown to be the most important in organ transplantation. Of these six antigens, we inherit three from each parent.
Except in cases of identical twins and some siblings, it is rare to get a six-antigen match between two people, especially if they are unrelated. Kidneys are very successfully transplanted between two people with no matching antigens.
A person can make antibodies against another person’s HLA antigens. Antibodies can result from blood transfusions, pregnancy, infections or even a viral illness. Having one of these events does not mean a person will make antibodies but they could. If a recipient has strong antibodies against a donor’s HLA, the risk of rejection is high and a donor would be declined for that recipient.
As a seasoned expert in the field of organ transplantation, particularly kidney transplantation, I bring a wealth of knowledge and hands-on experience to shed light on the intricacies of the three critical tests involved in the evaluation of donors: blood type, crossmatch, and HLA testing.
First and foremost, let's delve into the foundational aspect of blood typing, a pivotal step in the living donation process. The importance of blood type compatibility cannot be overstated, as it serves as the initial determinant of whether a potential donor is a suitable "match" for the intended recipient. With four distinct blood types—O, A, B, and AB—it is imperative to adhere to the well-established rules governing blood type compatibility, mirroring those observed in blood transfusions. Notably, individuals with blood type O are considered universal donors, capable of giving to any other blood type, while those with blood type AB are deemed universal recipients, able to receive organs or blood from donors of any blood type.
The chart provided succinctly outlines the permissible blood type donations, reinforcing the significance of this preliminary assessment in ensuring a successful transplant:
- If your blood type is O, you can donate to these blood types: O, A, B, AB.
- If your blood type is A, you can donate to these blood types: A, AB.
- If your blood type is B, you can donate to these blood types: B, AB.
- If your blood type is AB, you can donate to these blood types: AB.
Now, let's transition to the crossmatch, an essential evaluation beyond blood typing. This test assesses the compatibility between the donor's and recipient's blood, ensuring there are no unforeseen complications that could lead to rejection.
Finally, the intricate realm of HLA typing, often referred to as "tissue typing," comes into play. HLA, or human leukocyte antigen, involves six critical antigens inherited from each parent. While achieving a perfect six-antigen match is rare, kidneys can still be successfully transplanted with no matching antigens. Importantly, the risk of rejection is heightened if the recipient develops strong antibodies against the donor's HLA, which can result from various factors such as blood transfusions, pregnancy, infections, or viral illnesses. Consequently, donors with a high risk of rejection due to antibody presence are typically declined for the intended recipient.
In conclusion, the comprehensive understanding of blood type compatibility, crossmatching, and HLA typing is paramount in ensuring the success and viability of kidney transplantation. These tests collectively form the cornerstone of the meticulous donor evaluation process, guiding medical professionals toward making informed decisions that optimize transplant outcomes.
