An alcohol urine test involves a lab testing a person’s urine sample for the presence of alcohol. Three types of this test exist. One measures unmetabolized alcohol, while the others measure two of its metabolites, or breakdown substances.

In an interview with David Seitz, MD, medical director for Ascendant Detox, he said that all three tests are accurate.

The test for unmetabolized alcohol can detect it up to 12 hours after alcohol consumption. The tests for metabolites can detect them up to 80 hours after alcohol consumption. Because the tests are very sensitive, using products or eating foods with tiny amounts of alcohol may affect results.

This article discusses an alcohol urine test, including accuracy, testing methods, factors that affect detection, and products to avoid before a test. It also examines how long alcohol stays in urine and whether it shows up in a drug test.

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“An alcohol urine test is one way of measuring the presence of alcohol in a person’s system,” said Seitz. “There are three types. Two of them involve measuring the alcohol metabolites ethyl glucuronide (EtG) and ethyl sulfate (EtS). The third test measures ethyl alcohol (EtOH), which is alcohol that has not undergone metabolism.”

Are the tests accurate?

In general, all three urine alcohol tests can be quite accurate when testing for alcohol consumption.

“They are usually very sensitive and can detect alcohol that a breath test may not pick up,” Seitz said. “Doctors consider the EtG test one of the most accurate types. This is because it can reveal even trace amounts of alcohol, and it has a longer detection window than other tests.”

Researchers in a 2020 study agree on the test’s accuracy. They report that EtG is sufficiently reliable as an objective biological indicator of alcohol use. Because self-reports of alcohol use have the potential to be unreliable, the authors conclude that EtG is an effective supporting tool to accompany self-reports.

“EtG and EtS together can produce even more accurate results,” Seitz said. “The EtOH is also relatively accurate but has a shorter detection window than the EtG and EtS tests.”

Urine alcohol tests usually do not cause any discomfort, so they are relatively safe and noninvasive.

“They take little time, and the results are usually available within 1–2 days,” said Seitz. “Typically, they involve collecting a sample of the person’s urine in a clinic or doctor’s office, which is sent to a laboratory for testing.”

He added, “Additionally, at-home urine testing kits are on the market that makes it possible for people to collect and test their own samples. These tests use a simple strip method that is similar to that of a pregnancy test, and the results are available within minutes.”

Testing methods

Lab technicians examine the urine sample for the presence of EtG, EtS, or EtOH. They use a variety of methods, including:

  • Gas chromatography-mass spectrometry: This procedure uses heat to separate the urine sample into its components, after which it measures its mass.
  • Liquid chromatography-tandem mass spectrometry: This is similar to the above but uses a liquid solvent rather than a gas to separate urine components.
  • Enzymatic assays: This is a measure of enzyme activity within a sample.

In each case, once complete, they generate a detailed report, which can confirm or deny recent alcohol consumption.

“Usually, tests can detect the presence of EtOH in a person’s urine within an hour of consumption,” said Seitz. “It remains detectable for up to 12 hours afterward, depending on the type of test being used. In contrast, the EtG and EtS tests are much more sensitive and can detect alcohol up to 80 hours after consumption.”

Yes, blood tests for drugs can detect alcohol as well, notes research from 2016. They generally reveal unmetabolized alcohol rather than a metabolite.

While the primary factor involves the amount and duration of alcohol consumption, other factors may play a role. These include:

Weight

“A person’s weight can affect the results because heavier people metabolize alcohol more slowly than those who are lighter,” said Seitz. “An individual with a higher body mass index (BMI) may have EtG in their system for longer periods of time compared to someone with a lower BMI.”

Age

“As people get older, their bodies become less efficient at metabolizing alcohol,” said Seitz. “This could result in higher levels of EtG detection in their urine.”

Medications

Seitz notes that the following medications can affect test results:

“This is why it is important for people to tell their doctor all of the medications they take,” he said.

Storage and transport

“Individuals should store urine samples in a sealed container and transport them within a reasonable time for an accurate result,” said Seitz. “If too much time passes before testing the sample, the EtG in the urine could break down and cause a false negative result.”

Certain products and foods can produce a false positive when a person has not consumed alcohol.

“Since the urine test is highly sensitive, it can sometimes detect trace amounts of alcohol that can be present in non-alcoholic items, such as mouthwash and antiperspirant,” said Seitz.

Certain food products also contain alcohol, such as:

  • vanilla extract
  • balsamic vinegar
  • kombucha, a fermented beverage

“Because of this, it is important to rule out all possible sources of EtG before making any conclusions based on an alcohol urine test result,” added Seitz. “Medical professionals may also use other tests in conjunction with the urine test to get a more accurate picture of a person’s level of alcohol consumption.”

People can take an alcohol urine test in a clinic, or they can use an at-home test. Either method indicates whether they have recently consumed alcohol.

The EtOH test can detect alcohol up to 12 hours following consumption, while the EtG and EtS tests can detect it up to 80 hours following consumption. All three tests are reliable and accurate.

Blood tests for drugs may also detect unmetabolized alcohol.

Factors that affect detection include the amount and duration of drinking, as well as weight and age. Storage and transport methods may also have an influence.

Additionally, because some medications can affect results, individuals should disclose all the drugs they take to their doctor. Before a test, they should also avoid the use of products and eat foods that contact trace amounts of alcohol.