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NLRB update - MMaT calculation now based on DSA of transplant hospital

Published on: Thursday, May 23, 2019

Key updates and actions:

  • MMaT now calculated by DSA of liver transplant hospital
  • Scores converted as of 10:15 p.m. EDT May 24
  • Waiting time may be adjusted upon request if MELD exception score increased
  • Median PELD at transplant (MPaT) is not affected

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Effective May 24, 2019, at 10:15 p.m. EDT, the median MELD at transplant (MMaT) scores for liver candidates with exception scores are now based on recent liver transplants performed at liver transplant hospitals within the donation service area (DSA) where the candidates are listed.

When the National Liver Review Board (NLRB) was implemented on May 14, 2019, at the same time as the acuity circles distribution model, the basis of the MMaT calculation was recent transplants at all liver transplant hospitals included in a 250 nautical mile radius of the hospital listing the exception candidate.  With the reversion to a donation service area (DSA) and region-based liver allocation system effective May 23, some DSAs had different MMaT scores among liver programs within their area.  This in turn could create disparities affecting candidates’ transplant access within the local DSA of the donor.

The OPTN Executive Committee, by teleconference May 24, unanimously approved basing the MMaT calculation on DSA to address unintended consequences of the reversion to DSA-based liver allocation. 

The conversion has been made within UNetSM for all liver transplant candidates who had an exception score based on MMaT within a 250 nautical mile radius.  Please refer to this table for the MMaT score for each liver transplant program based on DSA.  If you wish to compare it to the MMaT based on 250 nautical mile circles, this table lists the previous scores.

Many individual candidates’ MMaT will remain the same under the conversion as it was under the previous calculation.  Other candidates will have their exception scores either increase or decrease. 

You may apply to UNOS to have a candidate’s waiting time adjusted only if the candidate experiences an increase in their MELD exception score as a result of this action.  The waiting time adjustment will include time the candidate had at a lower exception score from the May 14 initiation of NLRB up until this action. To request a waiting time adjustment for a candidate, please submit a Waiting Time Modification form.  These forms are located in UNetSM; navigate to the WaitListSM, then on the top menu select “Resources”, then select “Forms/Tools.”

Median PELD at Transplant (MPaT) is unaffected by this action.  MPaT is the same for all transplant programs with PELD exception candidates and will remain at 35.

As always, transplant programs may request individual exception scores for candidates by the procedure set forth in OPTN Policy 9.4 (MELD or PELD Score Exceptions).

If you have questions about data or information systems, contact UNOS Customer Service at 800-978-4334.  For policy-related questions, send an e-mail to