The National Liver Offering Scheme
A system for prioritising people on the liver transplant waiting list
With the growing numbers of liver related illness, and a transplant system where the supply of donor organs does not meet the demand, donor livers are precious and must be put to the best use possible. This is a challenge that NHSBT, the blood and transplant authority for the UK, has addressed and in 2018, moved to a new system called the National Liver Offering Scheme (NLOS).
The purpose of the NLOS is to save as many lives as possible and get the best use possible out of all donated organs. The more detailed analysis of both recipient requirements and donor features increases the likelihood that the right liver will be offered to the right person at the right time.
The ethical considerations in offering organs are transplant benefit, need and utility.
- Transplant benefit - the difference between a patient’s expected survival if receiving a particular donated liver and the patient’s expected survival without a transplant.
- Need - how much someone needs a transplant. For example, if someone has acute liver failure from a virus or a paracetamol overdose, and if they don’t get a transplant they might die straight away; they need a transplant urgently.
- Utility - how much use the recipient will get out of the donated liver; how long that person will survive.
For an excellent summary of these principles, watch Dr Douglas Thorburn speak at our 2014 Patient Information Day at the Royal Free hospital, London. Since he presented at our meeting, NHSBT has moved to the Liver Offering Scheme which is now based on ‘transplant benefit' (from 30m57s to 32m58s):
The UK Liver Advisory Group agrees that ‘transplant benefit’ based offering is the optimum approach [92]. Transplant benefit integrates elements of a patient’s need for a transplant and a patient’s utility from receiving a particular donated liver. It also takes into account information about that donated liver. In this way, the NLOS can look at everybody on the waiting list to decide who is the best match for the next available liver.
What is UKELD?
UKELD stands for United Kingdom Model for End-Stage Liver Disease. UKELD is a scoring system that gives the doctors an indication of how severe the liver disease is. It was developed from the Model for End-Stage Liver Disease (MELD) score, which is based on blood tests scores from bilirubin, INR (blood clotting amount), serum creatinine (measure of kidney function) but UKELD includes sodium levels in the blood. It was a very good predictor of which patients may die soonest and was used as the basis of deciding who should be transplanted before the Liver Offering Scheme was introduced. The minimum UKELD score to get onto the waiting list was 49.
Transplant Benefit Score
The new system to decide who gets the next liver transplant uses a scoring system called the Transplant Benefit Score (TBS), which is more in-depth than the previous UKELD scoring system, and takes into account features of both patients on the waiting list and from the donor:
Recipient Factors
Age
Gender
Hepatitis C
Disease group
Creatinine
Bilirubin
INR
Sodium
Potassium
Albumin
Renal support
Inpatient status
Previous abdominal surgery
Encephalopathy
Ascites
Time on waiting list
Diabetes
Maximum AFP level
Maximum tumour size
Tumour numbers
Liver Donor Factors
Age
Cause of death
BMI
Diabetes
Donor type
Blood group
Split liver criteria
Transplant Benefit Score and Variant Syndromes
A small proportion of available organs will be offered to patients waiting for a liver transplant with Variant Syndrome (VS). VS refers to patients for whom the TBS is not appropriate and so their position on the waiting list will be prioritised according to waiting time. The frequency of organs offered to VS patients is based on the proportion of VS patients registered on the List (which at present is around three in every hundred organs offered).
National Offering System
Livers will be matched on a national basis rather than the previous regional basis, meaning all patients on the list are considered for the liver transplant (national allocation).