Once you’ve been listed for transplantation, you’ll be added to the United Network of Organ-Sharing (UNOS) waiting list. UNOS is the nonprofit organization that manages the nation’s organ transplant systems. You must be added to the waiting list even if you have a living donor available.
Your Position on the Kidney Waiting List
It is difficult to predict when a kidney from a deceased donor will become available for you. The wait list is divided by the blood group: A, B, O, and AB. Every person will be in his or her individual blood group while waiting for the deceased donor organ. Blood types must be compatible. Certain blood types such as B or O will usually have longer waiting time than others because of the scarcity of donors. Also, patients with many antibodies to different HLA antigens (structures on the transplanted kidney that your immune system recognized as “foreign”) will wait longer. Finally, some geographic regions have fewer organ donors than others, so patients in these regions wait longer for all types of transplants. For most people, the length of time spent on the waiting list determines when a kidney will become available for them.
A new kidney allocation system went into effect on December 4, 2014; its intent is to match kidney donors and recipients with the best survival potential, to increase the chance of transplanting people with many antibodies to HLA antigens, and attempt to decrease the number of discarded kidneys. Priority points are given for various things, and the candidate with the most points AND a compatible cross-match will be offered the kidney.
Some of the important points of this system points are explained below:
1. EPTS and KDPI Scores
Two scores that describe potential post-transplant survival were created and are described below.
For Patients – the EPTS score = Expected Post Transplant Survival score
This is based on four factors:
- Time on dialysis
- Current diabetes status
- Previous solid organ transplant
For Donors – the KDPI score = Kidney Donor Profile Index score
This score is an estimate of how likely a kidney will fail. Multiple donor factors are used to calculate the score including the potential donor’s:
- Diabetes status
- Cause of death
- Serum creatinine
- Hepatitis C virus status
- Donation after cardiac death status
Each of the factors used to determine the scores are known to affect survival (EPTS) or kidney function after transplantation ((KDPI).The scores are shown as percentages(from 1 to 100%) with the lower numbers indicating better survival or function. Kidneys with a KDPI of 20% or less will be offered first to adult candidates with EPTS of 20% or less and then to patients with higher EPTS scores taking into consideration length of time on the waiting list and HLA antibody status.
You will be asked to sign a separate consent if you are willing to accept a kidney with a KDPI score of 85% of greater. These kidneys have a lower expected survival rate than kidneys with low scores, but more than half will still be functioning 5 years after transplantation. Your transplant doctor will discuss this with you in detail and answer all questions you may have.
2. Sensitized Candidates
“Sensitized candidates” refers to patients who have developed antibodies to one or more HLA antigens. Antibody to the HLA antigen develops when a person is exposed to another person’s blood or tissue through blood transfusion or previous organ transplantation. You cannot receive a kidney if you have an antibody to one of its HLA antigens because the presence of your antibody against the HLA antigen will lead to the process of rejection. Rejection is a process whereby your body will attack the organ in an attempt to destroy it. The more antibodies that a person has against different HLA antigens, the more difficult it is to find a compatible kidney. The new allocation system assigns priority points to patients with these antibodies, with more points being given for larger number of antibodies. Patients who are highly sensitized (those who react to 98% or more of likely HLA antigens) receive both regional and national priority for available kidneys. The extra priority points are given in the following way: 24.4 (98%), 50.09 (99%), or 202.1 (100%) points to the waiting time of these highly sensitized patients.
3. Waiting Time
In the past, the date a person was placed on the UNOS waiting list, he or she begins to accrue time from that moment onward. In the new system, patients receive waiting time credit for time spent on dialysis before being placed on the waiting list.
While you’re waiting for a kidney to become available, we will need monthly blood samples sent to the laboratory to test for antibodies. This is to make sure that a current sample of your blood will be available for cross-matching if a kidney should become available for you. Your coordinator will work with you or your dialysis center to arrange this monthly blood test.
Staying Active on the Kidney Waiting List
UNOS has established guidelines you must follow in order to remain eligible for a kidney transplant. It is your responsibility to abide by these guidelines:
- Abstain from non-prescribed drugs and tobacco.
- Keep all scheduled appointments.
- Follow all the recommendations from the multidisciplinary transplant team.
- Obtain laboratory testing according to the schedule we will give you.
Communication with Our Transplant Center
It is very important that you call us to inform us of any of the following situations:
- Admission to another hospital
- A visit to the Emergency Room
- Diagnosis of an infection of any type
- Any changes in contact information including address and phone numbers for you and/or your primary contact person
- If you have changed your dialysis center
- Any changes to your insurance coverage, including prescription plans
- Travel plans that would affect your ability to reach Lahey Hospital & Medical Center within two hours (in case a kidney becomes available for you)
- If you are unable to keep any scheduled appointments at the transplant center