Who Can Donate a Liver: Eligibility, Safety and Regrowth

A living liver donor must be a relative of the patient, aged 18 to 55, otherwise healthy and ideally of a compatible blood group. Dr. Ashish George, Principal Consultant & Unit Head Liver Transplant, Fortis Hospital, Shalimar Bagh, New Delhi, India, explained that the remaining part of the donor's liver regrows to almost its original size within six months, and that donation does not shorten a donor's life.

Living donation raises the questions families ask first: who can donate a liver, whether it is safe, how quickly the liver grows back and what life looks like afterwards. This article answers each in turn. Why a patient needs a transplant in the first place is covered in the complete guide to liver transplant.

Who can donate a liver?

Dr. George separates eligibility into two questions: whether the law allows the person to donate, and whether medicine says it is safe and effective.

The legal requirement

Whoever is evaluated as a donor has to be a relative of the patient. In India, living organ donation is governed by the Transplantation of Human Organs and Tissues Act, 1994, and every donation is reviewed by an authorisation committee before surgery. Families travelling for a transplant should therefore expect the donor to be a family member and to document the relationship.

Blood group compatibility

Medically, the best donor is one whose blood group is compatible with the patient's. The rules are the same as for a blood transfusion:

• Patient group A: donors of group A or O are compatible.
• Patient group B: donors of group B or O are compatible.
• Patient group AB: a universal recipient, compatible with any donor group.
• Patient group O: only a group O donor is compatible.

Whether the blood group is Rh positive or negative does not matter in liver transplant.

If no one in the family has a compatible blood group, an incompatible donor can still be evaluated. In that case the patient needs preparation before the transplant, typically treatment to lower the antibodies against the donor's blood group. Dr. George was clear about the trade-off: the preparation takes slightly longer, there is an added cost, and the risk rises slightly. Indicative liver transplant costs are published separately.

Age and general health

The donor should be between 18 and 55 years of age and otherwise healthy. Dr. George listed the conditions that rule a donor out and those that do not.

A donor should not have:

• diabetes
• advanced lung disease
• any other uncontrolled condition that poses a risk to life

The following are usually not a barrier:

• mild hypertension
• previous abdominal surgery
• benign gynaecological problems
• mild bronchial asthma
• a seizure disorder controlled on medication

These history-based criteria broadly define which relatives the team will go on to evaluate for donation.

How a living liver donor is evaluated

Both the patient and the donor undergo extensive evaluation. For the donor, Dr. George described the assessment as two-pronged:

1. Safety for the donor. The surgery itself must not pose any major risk to the donor.
2. Quality of the liver. The liver must be good enough that the part placed in the recipient works well.

The assessment typically combines blood tests, a check of heart and lung fitness, and imaging of the liver to measure its volume, map its blood vessels and bile ducts, and look for fat. Measuring volume shows whether the portion to be donated will be enough for the recipient while leaving the donor a safe remnant.

Liver quality is a spectrum. A younger donor with a liver free of fat will usually give a better-quality graft (the transplanted portion of liver) than an older donor whose liver carries a little more fat. Donors towards the less favourable end of that spectrum are called marginal donors. When the team declares a donor fit, Dr. George explained, both aspects have already been weighed: the risk to the donor is minimal and the quality of the liver is good enough.

How often does a donated liver fail to work?

Rarely. The chance that the transplanted liver does not work at all, called primary non-function, is less than 1 to 2 percent in living donor transplant, according to Dr. George. Sometimes the new liver takes time to function well, a condition called early allograft dysfunction, which may occur in about 5 to 10 percent of patients.

How much liver is taken, and how fast does it grow back?

By six months, the donor's remaining liver has regrown to almost 95 to 97 percent of its original size. In adult living donor transplantation, about 60 percent of the donor's liver is removed and about 40 percent remains. That remaining liver grows very fast. Experimental data in rats and imaging studies in humans show the pattern Dr. George described:

• First 2 to 4 weeks: growth is fastest, and 70 to 80 percent of the regrowth happens in this period.
• 3 to 6 months: growth continues more slowly.
• By 6 months: the liver has reached almost 95 to 97 percent of its original size.

Why the liver is different from the kidney

Dr. George used the kidney to show what makes the liver unusual. Suppose each kidney holds 50 nephrons, the filtering units. When one kidney is donated, the 50 nephrons left behind have to work overtime to look after the body, and their number never rises to 60, 70 or 100.

The liver behaves like a tree. Cut away 70 to 80 percent of its branches, give it sunlight, manure and water, and in three to six months it is whole again; no one would know it had been pruned. The donor's liver does the same.

Is liver donation safe? The 10-year myth

Liver donation does not shorten a donor's life. Dr. George called the claim that a donor has only 10 years to live an absolutely false statement. Whatever risk the donor carries is concentrated around the time of the operation, because liver donation is major surgery. Once the donor has recovered, that risk is behind them.

His account of the donor's recovery:

• Hospital stay: 95 percent of his donors are discharged within five to six days.
• One month: by the end of the first month most donors fly back home, and they need no further follow-up with the transplant team after that.
• Three months: the scar takes about three months to reach its normal strength, so donors are told not to lift heavy weights for that period.
• Long term: the donor takes no long-term medication.

Apart from the three-month lifting restriction, nothing changes. Food habits, social life, family life, life expectancy, work, sexual life and having children are all unaffected. Whatever life the donor lived before the donation, they continue to live after it.

Can a person donate part of their liver twice?

No. A person can donate only once.

Cold ischaemia time: living versus deceased donor

The time a liver spends outside the body, cooled and without a blood supply, is called the cold ischaemia time. It matters because the longer the liver is kept without blood, oxygen and nutrients, the more of its cells die.

The two sources of liver differ sharply on this measure:

• Deceased donor. A whole liver taken from a brain-dead donor can be kept in preservative solution for up to 16 hours and still be transplanted successfully, though the team wants that time to be as short as possible.
• Living donor. The donor and recipient operations run side by side in adjacent operating theatres. The liver is outside the body for perhaps half an hour to one and a half or two hours, the time needed to prepare it for implantation.

Dr. George described this as a key benefit of living donor over deceased donor transplant. It also allows the operation to be planned, which matters for patients whose condition or tumour should not wait. The role of planned living donation in liver cancer is discussed in liver transplant for liver cancer: HCC, the UCSF criteria and downstaging.

Can a healthy person store part of their own liver for later?

No. An attendee asked whether a healthy person could have part of the liver removed and stored, to be transplanted back if liver disease developed later. Dr. George's answer was that this has not been considered or done, for three reasons:

1. Few people will ever need it. Only a very small subset of the population develops liver disease, and only some of those go on to liver failure that requires a transplant.
2. The operation is not justified. Removing part of the liver is itself major surgery, and it is not advisable in a healthy person.
3. A liver cannot be stored for years. A graft can be kept outside the body for a few hours, and machines can keep deceased-donor organs for a few days, but nothing beyond that.

For the recipient, the next stage is the long term: survival, immunosuppression, diet and the rules on alcohol, all set out in liver transplant survival rates and life after surgery. Other questions doctors raised in the session are answered in the Live Discussion.