Transplant centers around the country have different rules about how potential liver recipients’ use of cigarettes, drugs or alcohol affects their chances of receiving an organ. Transplant experts discussed the issue this week at the annual meeting of the American Association for the Study of Liver Diseases.

“You don’t want to waste a liver, but you don’t want to deny a patient a life-saving therapy either, just because he’s a smoker,” said David Riech of Hahnemann University Hospital in Philadelphia. “A lot of people who need liver transplants are smokers.”

The experts said there is not enough information on the impact of various addictions on transplants, MD Magazine reports. Transplant surgeons also may have personal biases when making decisions about who gets a liver, the experts noted.

Michael Lucey, MD of University of Wisconsin School of Medicine in Madison, conducted a survey of 42 transplant centers, which together perform about half of liver transplants in the United States. He found a wide variety of policies on transplants. Of the 42 centers in the survey, 24 said they require a set period of abstinence from alcohol before a liver transplant can be done. An additional 15 centers said “it depends,” and one said no.

The survey found 27 centers required a six-month period of abstinence from opiates. Few transplant centers required patients to be in a smoking cessation program, Lucey found.

Most centers had no marijuana policy. The experts agreed the question of marijuana use and its affect on the liver is virtually unstudied. They noted there have been a few cases of a fungal infection called aspergillosis in marijuana-smoking patients who received liver transplants, but there is no data on the risk.

While giving a new liver to a recovering alcoholic can be risky because the patient faces a danger of relapse and damaging the new liver, the risk of relapse is unknown, the article notes.