Australian researchers have found that a blood test can provide doctors with a much clearer picture of recent alcohol use in people with liver disease.
The test may be particularly useful when doctors need accurate information to guide treatment or assess patients for a liver transplant.
Alcohol can damage the liver because this organ does much of the work of breaking alcohol down. Long-term heavy drinking can lead to fat buildup, inflammation, scarring and eventually severe liver failure.
But alcohol is only one cause of liver disease. Excess body weight, diabetes, viral hepatitis, immune system disorders and other conditions can also damage the liver, and some people have more than one cause at the same time.
Knowing whether a patient is drinking can therefore be important for doctors trying to understand why liver damage is continuing. It can also help them decide what treatment, counseling or other support a patient may need.
Traditionally, doctors have often relied on patients to describe how much alcohol they drink. Other blood tests can provide clues, but many are not specific to alcohol and can be affected by liver disease itself or other health problems.
The newer test measures a substance called phosphatidylethanol, usually shortened to PEth. Unlike many other markers, PEth is formed in the blood only when alcohol is present.
This means that finding PEth provides strong evidence that a person has consumed alcohol. It can also remain detectable for several weeks, giving doctors a longer window into recent drinking than some older tests.
Researchers studied 183 people, including patients with alcohol-related liver disease, people with alcohol use disorder and healthy participants. The participants reported their alcohol intake, and the scientists compared these reports with PEth measurements and other commonly used tests.
The results showed that PEth was highly accurate at identifying recent alcohol use. The researchers reported that it detected drinking with about 95% accuracy and also provided useful information about the amount of alcohol consumed.
Higher PEth levels were generally linked with heavier drinking. A level around 300 micrograms per liter was associated with heavy alcohol use, while levels of 600 micrograms per liter or higher were linked with very heavy drinking.
However, a blood test cannot tell doctors every detail about a person’s drinking pattern on its own. Results need to be considered alongside the patient’s health, medical history and other clinical information.
One important finding involved people who reported that they had not been drinking. More than one-third of these participants had PEth results indicating recent alcohol use.
There can be several reasons for differences between self-reports and blood tests. People may underestimate how much they drink, have difficulty remembering their intake, misunderstand standard drink sizes or feel uncomfortable telling doctors about alcohol use.
Professor Devanshi Seth, one of the researchers involved in the work, said PEth provides a biological record of alcohol exposure. Because it can remain detectable for up to about five weeks, it may help doctors identify drinking that would otherwise be difficult to confirm.
The test could be especially valuable in liver transplant programs. Patients with severe liver disease often undergo detailed assessments before transplantation, and understanding recent alcohol use can be important for planning treatment, support and follow-up care.
Dr. Anastasia Volovets, a liver transplant specialist involved in the research, said objective information can help medical teams understand a patient’s situation more fully. The aim is not simply to catch people drinking, but to provide appropriate care and make well-informed medical decisions.
PEth testing is being introduced at the Liver Transplant Unit at Royal Prince Alfred Hospital in Sydney. The researchers hope the approach will eventually be used more widely in liver clinics and transplant services across Australia.
The study was published in the journal Alcohol: Clinical and Experimental Research. The findings suggest that PEth testing could give doctors a more reliable way to monitor alcohol use than relying only on traditional blood markers or what patients remember and report.
For people with serious liver disease, accurate information can make a major difference to care. A test that shows recent alcohol exposure over several weeks could help doctors identify risks earlier, offer support when needed and make better-informed treatment decisions.
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