Scientists have known for many years that blood group matching is important in transfusion and it is equally important in kidney transplantation. There are four major blood types. These types are simply noted as blood type A, B, AB and O. The positive or negative feature in blood typing is not a factor when determining compatibility between a donor and a recipient.
Blood Type Compatibility Chart
|Blood Type:||Can Donate To:|
|O||A,B, AB, O|
|A||A or AB (O)*|
|B||B or AB|
|Blood Type:||Can Receive From:|
|A||A or O|
|B||B or O|
|AB||A or B or AB or O|
|(Blood Type O is the Universal Donor: donors with O blood are compatible with any other blood type)|
|(Blood Type AB is the Universal Recipient: recipients with AB blood are compatible with any other blood type)|
|* Recently, it has been discovered that some donors with blood type A may donate to a blood type O recipient. Person with blood type A or AB and someone with blood type B may donate to a person with B or AB. A person with blood type AB may only donate to an individual who has that same blood type.|
About 20% of the people who need a kidney transplant have high PRA’s. Simply stated, having a high PRA will significantly limit the number of people that will be able to donate to you. You can develop high PRA’s from a blood transfusion, an earlier transplant or for some women, from being pregnant.
There are ways of lowering PRA’s through a procedure called Plasmapheresis a blood-cleansing process that can lower the dangerous antibodies from the blood. Plasmapheresis is usually used when you have an incompatible living donor.
Plasmapheresis can also been used to allow blood-type incompatible donor/recipients to proceed with the transplant. Plasmapheresis can cost tens of thousands of dollars and are complex to administer.
If you’ve been told by a transplant center that you are too highly sensitized, (another term used to describe high PRA's,) to receive a transplant ask about Plasmapheresis. If they don’t offer it there, speak to another transplant center.
Cross matching is a very sensitive and final test performed on a kidney donor and a particular recipient. Laboratory techniques for cross matching have been refined and now enable scientists and physicians to define how a kidney transplant recipient may respond to particular cells or proteins of the kidney donor. These refinements in testing have led to very accurate tests that were not available even a few short years ago.
The basic cross match test involves a mixing of cells and serum to determine whether or not the recipient of a kidney will respond to the transplanted organ by attempting to reject it. In recent years, scientists have applied more intricate tests and obtained more accurate results of cross matching. It is now possible to better indentify a recipient who might reject an organ and thus avoid a transplant that might not succeed. Thus, improved kidney transplant outcomes may ensue because we can better determine and predict how the recipient may respond to the donated organ. Cross match testing, therefore, has evolved and improved long-term results.
Cross match testing, which involves several different phases and, as many as 10 to 15 different tests, comes down to a fairly simple final result. Either the cross match is positive or negative. A positive cross match means that the recipient has responded to the donor and that the transplant should not be carried out. A negative cross match means that the recipient has not responded to the donor and therefore transplantation should be safe. A positive cross match (not what you want,) essentially says that the recipient will respond to the donor organ by rejecting it and the operation should not be performed. A negative cross match says to the recipient, you are not likely to reject the donor organ and the operation should be performed. If we look at the cross match in this way, the positive and negative results make sense to all concerned.
A well matched kidney is one in which the blood type between the donor and recipient are compatible, the tissue typing well defined and hopefully well matched and all cross match studies are negative. Application of good matching studies in clinical kidney transplantation has allowed for excellent results using living donor and deceased donor organs and has permitted safe kidney transplantation for thousands of patients with end-stage renal failure.