Kidney Protocol

The Allocation of Transplant Kidneys in Australia

Introduction:

The allocation of kidneys from a deceased donor to patients on the waiting list is determined by a computer program called the National Organ Matching System or NOMS. NOMS is administered by the Australian Red Cross. In most cases, only patients who have commenced dialysis will be eligible to be listed on the waiting list. The major criteria that are used by NOMS to decide who will receive the kidneys are:

  • The blood group (Most kidneys go to somebody who is the same blood group as the donor).
  • How long the patient has been on dialysis.
  • The Tissue Typing or ‘matching’ with the donor.
  • Whether the patient has a lot of antibodies against other people’s tissue types.
  • Whether the patient is a child as children get priority.

National Interstate Exchange Program:

NOMS runs a national matching program, which looks at all of the patients that are waiting in Australia to mainly identify patients who have a lot of antibodies against other people’s tissue types. This is important because these patients really need a very well matched kidney. It is much harder to find a suitable kidney for them, than for patients who do not have these antibodies. If somebody with a lot of these antibodies comes up as a very close match, the kidney can be sent to them from anywhere in Australia. This scheme covers patients who have high levels of antibodies and only 0, 1 or 2 mismatches with the donor. It also allocates kidneys to patients who have a perfect match with the donor, even if they have no antibodies. The exchange program also allows for kidneys to be sent from one state to another to maintain a balance between the states, so that an excess of kidneys do not move out of any one state.

About 20% (1 in 5) of all kidneys are shipped according to this Interstate Exchange program. The remaining 80% (4 in 5) kidneys are transplanted in the same state where they were donated. Again NOMS calculates who should receive the kidneys in each state, according to the state’s allocation formula. Each State Transplant Service uses a slightly different formula to take into account differences in the number of people waiting for a transplant, and other factors. The paragraphs below summarise the way that kidneys are allocated in each of the State Transplant Services.

There are some types of kidneys that are only allocated within the state in which they are donated. In this situation, the Interstate Exchange Program is not used, just a State-based program. These situations are where it is particularly important to transplant the kidney quickly, or where there are technical issues with the kidney that are best dealt with locally. Examples of these situations include kidneys donated after cardiac death (DCD donation), and kidneys donated by living patients after nephrectomy for renal pathology.

The National Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

Base Score -    0 HLA mismatches, Peak PRA not<50%        {Level 1}         60 000 000

Base Score -    1 HLA mismatch, Peak PRA > 80%                 {Level 2}         59 000 000

Base Score -    2 HLA mismatches, Peak PRA > 80%             {Level 3}         58 000 000
Base Score -    0 HLA mismatches, Peak PRA < 50 %            {Level 4}         57 000 000

Base Score -    0 mismatches at DR, 1 or 2 mismatches
                           at A or B, Peak PRA not >80% and Centre
                           Credit Difference <=-3                                         {Level 5}          56 000 000

Base Score -    0 mismatches at DR, 1 or 2 mismatches
                           at A or B, Peak PRA not >80% and Centre
                           Credit Difference <=-3                                         {Level 6}          55 000 000

Null Score -     and Centre Credit Difference <= -20                 {Level 7}          54 000 000

Paediatric Bonus – if age < 18, first dialysis before
15th birthday and on dialysis for > 1 year                                                             +     30 000

Recipient at same centre as Donor                                                                       +     50 000

Patient Centre Credit is not null                                              1000 + Patient Centre Credit

Patient Waiting Period > 0                                                                        + Wait in months * 1

If Score is < 54 000 000, go to Relevant State Based Algorithm

New South Wales / ACT:

After the national allocation has been taken into consideration, kidney allocation within NSW from deceased donors is according to computer algorithm.  This algorithm takes into account both matching and waiting time.  With increasing time spent on dialysis waiting time becomes more important.

National allocation currently does not occur for kidneys obtained from donation after cardiac death.  Extremely marginal renal allografts on occasion may be offered as a dual allograft based on donor criteria, findings at procurement and allograft biopsy results.  This only occurs once or twice a year.

The New South Wales Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

State HLA
Base Score if no Mismatches at DR                                                  50 000 000
For each mismatch at A                                                                        - 1 000 000
For each mismatch at B                                                                        - 1 000 000
Paediatric Bonus – if age < 18, first dialysis before
15th birthday and on dialysis for > 1 year                                           +     30 000
Patient Waiting Period > 0                                                + Wait in months * 100
Patient age <61                                                                                               +        1
If Score is < 48 000 000, go to State Waiting

State HLA
Base Score                                                                                               40 000 000
Paediatric Bonus – if age < 18, first dialysis
before 15th birthday and on dialysis for > 1 year                             +     100 000
Patient Waiting Period > 0                                                 + Wait in months * 100
Patient age <61                                                                                         +               1

Queensland: 

The Queensland NOMS programme primarily determines who will receive kidneys by HLA matching, or by the time a patient has been on dialysis. Firstly all patients on the waiting list, who are of the correct blood, group are matched against the donor. If there are any very well matched patients (no more than 2 mismatches out of 6) then the NOMS programme allocates it to the patients with the best match. This happens about 50% of the time. The other 50% of the time, there is nobody on the waiting list who is that well matched with the donor. In these cases NOMS ignores the matching altogether, and produces a list of compatible patients, in order of who has been on dialysis longest. A patient’s renal physician should be able to give them an approximate idea of how long it will take them to get to the top of the list for their blood group, and whether there are any special circumstances that might make it harder than usual for them to get a kidney.

The Queensland Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

State HLA
Base Score                                                                                                 50 000 000
For each mismatch at A                                                                           - 1 000 000
For each mismatch at B                                                                           - 1 000 000
For each mismatch at DR                                                                        - 1 500 000
Patient Waiting Period > 0                                                   + Wait in months * 100
If Score is < 47 000 000, go to State Waiting

State Waiting
Base Score                                                                                                  40 000 000
Patient Waiting Period > 0                                                    + Wait in months * 100

South Australia:

The South Australian NOMS programme determines who will receive kidneys by HLA matching and by the time a patient has been on dialysis. Firstly all patients on the waiting list, who are of the correct blood, group are matched against the donor. If there are any very well matched patients (no more than 3 mismatches out of 6) then the NOMS programme allocates it to the patients with the best match. This happens about 30% of the time. The other 70% of the time, there is nobody on the waiting list who is that well matched with the donor. In these cases NOMS ignores the matching altogether, and produces a list of compatible patients, in order of who has been on dialysis longest.

The South Australian Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

State HLA
Base Score                                                                                                  30 000 000
For each mismatch at A                                                                          - 10 000 000
For each mismatch at B                                                                          - 10 000 000
For each mismatch at DR                                                                       - 10 000 000
If total mismatches is > 3 then reset score to                                                          0
Patient Waiting Period > 0                                                          + Wait in months * 1

Victoria / Tasmania:

If Victorian patients do not fit the criteria for national allocation a starting score of 40,000,000 is assigned. Patients lose 20,000,000 for each B and /or DR mismatch. Therefore if a Victorian patient has 2 B and/or DR mismatches their score reduces to zero and any added scores are for months on dialysis. i.e waiting time only applies. However waiting time also applies in the matching list. For example if a patient has one donor DR mismatch and has been waiting 60 months for a graft the score will be 20,000,060.

The Victorian Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

State HLA
Base Score                                                                                                    40 000 000
For each mismatch at B                                                                            - 20 000 000
For each mismatch at DR                                                                         - 20 000 000
If total mismatches at B and DR is > 2 then reset score to                                     0
Patient Waiting Period > 0                                                           + Wait in months * 1

Western Australia:

The National Allocation Scheme will ensure Western Australian patients, particularly those who are highly sensitised, will be offered well matched kidneys from the National pool when available. After this allocation is taken into account, the Western Australian algorithm allocates kidneys based on a combination of HLA matching (tissue types) and waiting time. For patients with uncommon tissue types, the WA algorithm gives considerable emphasis on waiting time ensuring that with increasing time, they will receive priority above those with a better-matched kidney.

The Western Australian Computer Formula (as at March 2008) that is used to determine which patients have the highest priority for an available kidney is:

State HLA
Base Score                                                                                                      50 000 000
For each mismatch at A                                                                             -    3 000 000
For each mismatch at B                                                                             -    3 000 000
For each mismatch at DR                                                                          -    5 000 000
Patient Waiting Period > 0                                                + Wait in months * 100 000
Homozygous at DR and Waiting > 5 years                                             +   5 000 000


Date of protocol: August 2002; Revised March 2008