In the lung allocation system, every lung transplant candidate age 12 and older receives an individualized lung allocation score. The lung allocation score is an important factor in determining priority for receiving a lung transplant when a donor lung becomes available. The system determines the order of everyone awaiting a lung transplant by their lung allocation scores, blood type, and the geographic distance between the candidates and the hospital where the lung donor is located. Age also plays a role because lungs from pediatric and adolescent donors are offered first to pediatric and adolescent transplant candidates before they are offered to adults.
The lung allocation system uses medical information specific to each lung transplant candidate. This information includes lab values, test results, and disease diagnosis. This medical information is used to calculate a lung allocation which represents an estimate of the severity of each candidate's illness and his or her chance of success following a lung transplant. All candidates are placed in order for compatible lung offers according to their score: a candidate with a higher lung allocation score will receive higher priority for a lung offer when a compatible lung becomes available.
The supply of donor lungs is limited. The OPTN designed this allocation system to more effectively use the limited number of available donor lungs as well as reduce the number of deaths among people waiting for a transplant. Prior to this system, transplant candidates received donor lungs based on the amount of time they had been on the waitlist for transplantation. The OPTN designed the lung allocation score system by studying scientific data on lung transplantation and by drawing on prior experience with many types of patients with lung diseases. By offering donor lungs to candidates according to their medical characteristics instead of their waiting time, lungs will be directed first to candidates who have the most urgent need and who will have the greatest chance of success after transplantation.
Considering the unique circumstances for lung candidates under the age of 12, these candidates are not prioritized by lung allocation scores. Instead, a simple priority system based on a candidate's medical condition is used to order these pediatric lung candidates. These candidates are listed as Priority 1 or Priority 2, based on their medical condition. Those that meet criteria reflecting a more urgent status are listed as "Priority 1," remaining lung candidates in this age range are labeled "Priority 2." At the time a match is run, a candidate's pediatric priority will be used along with ABO blood group and distance from the donor hospital to determine the order for making offers to lung candidates. The priority classifications yield a lung allocation system that gives more consideration to a pediatric candidate's urgency, as compared to one that is exclusively dependent on waiting time.
The lung allocation system is responsive to your individual medical needs because it will help determine when you will receive an offer for donor lungs based on your particular medical information. Your lung allocation score or pediatric priority is based on your own medical information and will reflect the seriousness of your medical status before transplant. The lung allocation score also factors your likelihood of a successful transplant.
Waiting time plays a very limited role when allocating lungs to transplant candidates. Candidates will receive lung offers based mainly on their lung allocation scores or pediatric priority (for those candidates younger than 12 years old). Waiting time will be used to break a tie only if two or more lung candidates happen to have the same lung allocation score or pediatric priority, and these candidates are in the same OPO/geographic zone classification.
Your transplant team will decide with you when the time is right for you to be registered for a lung transplant. When that time comes, you will need a complete transplant work-up. During the transplant work-up, you will participate in a series of medical tests that will give your transplant center the information it needs to register you as a candidate for lung transplantation. This same information will also be used to calculate your lung allocation score.
Your transplant center must update most of your medical information every six months. Since the lung allocation system uses your own medical information to compute your lung allocation score, it is important that your transplant center has your most current information and test results. Your transplant center may also update your information in the system any time your physician thinks it is necessary to reflect a change in your condition, but your transplant center will be required to update most of your information at least once every six months.
Updating Pediatric Priority 1 Data: Like adult candidates, pediatric Priority 1 medical information must be updated at least once every six months. Six months after a candidate's anniversary date, and every six months thereafter, the system will check to see if a Priority 1 candidate's medical information has been updated. The anniversary date is the day they were added to the waiting list. If a center has not updated a candidate's information within that six-month window, the candidate will revert to Priority 2 until updated, qualifying information is submitted.
Much of the medical information that is needed to calculate your lung allocation score comes from diagnostic tests or medical procedures. If your transplant team decides that you should not perform these tests or undergo these procedures because of the severity of your condition, your physician may supply a best estimate of your medical information to be entered on the system instead. The Lung Review Board, a national group of transplant surgeons and physicians, will evaluate your doctor's request and determine if it is appropriate to use estimated information in the system instead.
There is no specific lung allocation score that will guarantee that you receive an offer for donor lungs. When donor lungs become available, a "match run" list is created to match the lungs with suitable candidates based on blood type, distance from the donor hospital to their transplant center, and age group. Candidates who are registered at transplant centers in the local area around the donor hospital, who are in the appropriate age group, and who also have a blood type that matches the donor will be offered the lungs in order of their lung allocation scores. The compatible candidate with the highest lung allocation score at that time will receive first priority to be offered the donor lung(s). If no appropriate recipient is found among the candidates closest to the donor hospital, potential compatible recipients at greater distances will be offered the lung(s).
Remember, you and your medical team at your transplant center will always have the option to decide whether a lung transplant is the right choice for you at that time, or whether the donor lungs being offered are right for you.
If your transplant physician or surgeon believes that you have exceptional characteristics, and that your needs are not adequately reflected by your lung allocation score, then your transplant center may ask the Lung Review Board to review your situation. Similarly, if a transplant physician or surgeon feels that a lung candidate younger than 12 has a medical condition comparable to Priority 1, but does not meet one of the criterion listed in policy, they may request the Lung Review Board to review the pediatric candidate's situation. The Lung Review Board is a national group of transplant physicians and surgeons who will consider your special circumstances and determine what steps to take.
As transplant professionals apply this system and learn from it, some changes will likely be required to better meet the needs of transplant candidates. In fact, this system is designed to be flexible and allow for improvements. For example, the lung allocation score was first implemented in 2005 and the simple priority system for pediatric candidates younger than 12 was implemented in 2010. In organ transplantation, as in all scientific fields, new studies are taking place all the time to learn how to save more lives and how to help people live longer and fuller lives. The lung allocation system is reviewed periodically, and adjustments may continue to be made to the way lung allocation scores are calculated. Your transplant team will keep you informed of changes to the system and what you may need to do.
If you have any further questions or concerns, you should contact your transplant team. You may also contact the UNOS Patient Services Department at 1-888-894-6361.
