Mathematical system used to rank patients awaiting transplants

By Debi Palmeri, RN

What's your MELD Score? If you have liver disease you may have heard the term MELD bandied about by your physician or other members of your healthcare team. It is a relatively new term, and stands for Model for End Stage Liver Disease. MELD is a complex mathematical formula used to prioritize patients waiting for liver transplants.

Your MELD score is calculated by taking three lab tests, plugging them into the formula and coming up with a number. These three tests are bilirubin, INR and creatinine. The bilirubin number indicates how well your liver is excreting bile. The INR measures the liver's ability to manufacture certain clotting facots. And the creatinine measures kidney function, which can be affected by advanced liver disease. The scores range from 6 in a healthy person to 40. A person with a MELD score of 40 might very well be quite ill and in a hospital intensive care unit.

The purpose of the MELD scoring system is to use an objective measure to access how soon a person will need a liver transplant. The patient with the highest MELD score will get the liver when a donor is found. This is done to assure that the sickest patients get the transplant first.

The old scoring system used the length of time a patient had spent on the waiting list, as well as a few subjective measures, to rank patients. That system was disadvantageous for people with chronic liver disease who became seriously ill quickly. Under the old system, it was possible for a relatively healthy person to receive a liver before someone who might not survive without a timely transplant, simply because he or she had spent more time on the waiting list.

Because the MELD score is based on lab work, it can vary each time a patient has lab work done. Once a patient is on the transplant list he or she must have blood work done at scheduled intervals. People with high MELD scores may need weekly lab tests, while someone with a very low score might only be required to undergo lab tests every six to 12 months. This guideline does not mean that your physician might not want lab tests performed more frequently; rather, it is only what is required to stay active on the computerized transplant waiting list. A patients transplant team keeps track of his MELD score and will notify him when he needs to have lab work done.

And speaking of the computerized transplant list... The organization that manages the list is called UNOS (United Network for Organ Sharing). It is a non-profit, charitable organization located in Richmond, VA. UNOS operates under contract from the federal government. All patients who are listed in the United States are placed in this national computer system. When a liver becomes available in the patient's area, the computer will do a match run between the potential donor and potential recipients. The UNOS computer will provide the transplant center with a list of appropriate recipients based on blood types and MELD scores.

If a transplant center were to skip patients at the top of the list it would have to provide a reason for that action to UNOS. This is done to ensure fairness and equity in the organ allocation system.

Interested in your MELD score? Patients can go to the UNOS web site and plug their lab numbers into the system. Here's the formula: MELD SCORE= 0.95 x LOGc (creatinine g/dL) + 0.378 x Logc (bilirubin mg/dL) + 1.120 x Logc (INR) + 0.643.

Debi Palmeri, RN, CCTC, is transplant coordinator at Hartford Hospital.

References: As published in Special DLivery, May 2005, Vol. 22, Issue 2, News from the Connecticut Chapter of the American Liver Foundation.