When you and your doctor agree it is time for you to be evaluated for a transplant, you undergo a series of tests to assess your options. You’ll be evaluated for potential issues like heart disease, obesity, and diabetes. A social worker or transplant coordinator will discuss the logistics with you as well; things like transportation, housing, financial and family support will all be considered.
There are several screening tests to determine your blood and tissue type which are needed to match you to a donor kidney. In addition to the tests below, other tests may be required depending on your age, medical history, etc. A mammogram, colonoscopy, or other tests may be required.
Blood type is the first test; it will tell you which of the four blood types – A, B, AB, or O, you are. You must have a blood type that is compatible with your donor for the transplant to be successful.
Compatible blood types:
- If your blood type is A, donor blood type must be A or O
- If your blood type is B, donor blood type must be B or O
- If your blood type is AB (universal recipient), donor blood type must be A, B, AB or O
- If your blood type is O (universal donor), donor blood type must be O
The Rh type (+ or -) is not a factor in donor matching.
Human leukocyte antigens (HLA)
Human leukocyte antigens (HLA) (also called tissue typing) is the second blood test you’ll undergo. The HLA are found mostly on white blood cells; they are markers that let your immune system know which cells belong to your body and which do not.
Crossmatch is another blood test you will undergo. This test tells you what antibodies you have in your body. Antibodies are produced by your immune system when it attacks foreign substances. You make antibodies when you have an infection, are pregnant, have a blood transfusion or undergo a kidney transplant. If you have antibodies to the donor kidney, your body will fight that kidney until it is destroyed. The crossmatch test is done by mixing your blood with cells from your donor. If the crossmatch is positive, you have antibodies against your donor and should not receive the kidney.
All of these blood tests, along with the discussions mentioned above, are all required before you can be considered for a transplant. Once the results from all the tests are back, your transplant team will meet to discuss your results. They will discuss your medical and social history (history of drug or alcohol abuse, level of family and financial support, etc.) and make a decision. If they decide you should be listed for a transplant, you are then placed on the United Network for Organ Sharing (UNOS) waiting list.
The distance between you and your transplant center(s) is very important. Once you have been notified that a kidney is available, you will have a limited amount of time to get to the center. The less time the organ must be held outside the donor’s body will mean a better chance that the kidney will function when transplanted. There are three geographic levels to consider:
- Local: this is your local area and is served by the local organ procurement organization (OPO). There are 58 OPOs in the U.S.; they are typically state-wide but can be smaller or larger. Your transplant center will tell you what your local area and OPO is. An available organ will be offered within the OPO first.
- Region or zone: if the local OPO does not find a suitable match for an organ, they can be offered to patients at centers in a wider area. Kidneys are first offered within one of 11 regions of the U.S.
- Nationwide: if there are no local or regional matches, kidneys can be offered to anyone in the U.S. who is a potential match.
Most candidates are listed at a single transplant center, but some people choose to register at two or more transplant centers, called multiple listing, to potentially increase their chances of receiving a kidney. Unfortunately, there is no guarantee that multiple listing will shorten waiting time. Of the many factors affecting how long you will wait, location is only one. Multi-listing may offer more benefit to some patients than others and this should be discussed with your nephrologist or local transplant team.
Restrictions and considerations
The Organ Procurement and Transplantation Network (OPTN) has a policy to allow for multiple listing. That said, it is up to each individual transplant center to decide if they will accept you as a transplant candidate. Multiple listing in the same local area will probably not be of much benefit, even if you are listed at multiple hospitals. Some centers may have policy against accepting multiple-listed patients.
You must be considered and accepted as a transplant candidate at each center you want to be listed. This could include completing the full medical evaluation and agreeing to conditions set by the center. You will need to check with your insurance provider to understand how the cost of additional evaluations will be covered (they may only cover the cost of one evaluation). You’ll need to maintain current lab results and contact information for each center.
Waiting time is an important factor when waiting for a kidney transplant. The longest amount of time you have waited at any center is called your primary waiting time. If you are listed at multiple centers, your waiting time will start from the date each individual center listed you (unless you started dialysis before your first listing in which case they all date back to the dialysis start date). You can transfer your primary waiting time to another center (where you are listed) or switch time waited at different programs. All requests to transfer or switch waiting time must be approved by all involved centers.
Transfer of care
You may want to end your listing at one center and transfer it to another. You can do this as long as you coordinate with both programs. The new center will generally ask you to put your request in writing. It is very important to note that if you end your listing at one center before your new center formally accepts you, you may not be able to continue to accumulate waiting time.