EtG Test for Confirming Alcohol Abstinence

Medically reviewed by

Updated on October 15, 2019

The ethyl glucuronide (EtG) test is widely used to detect the presence in the urine of ethyl glucuronide, a breakdown product of ethanol, the intoxicating agent in alcohol. It can also screen for EtG in your blood, hair, and nails, but the urine test is the most widely used. The main purpose of an EtG test is to document alcohol abstinence.

What the EtG Test Is Used For

The test for EtG is widely used to detect alcohol abstinence in situations that do not allow drinking, including:

Alcohol treatment programs
A DUI or DWI program
Liver transplant patients
Schools or the military
Professional monitoring programs (for example, airline pilots, healthcare professionals, attorneys)
Court cases (for example, child custody)
Probation programs

It's important to note that the EtG test is not recommended for use in workplace testing programs as it does not measure current impairment from alcohol.

Detection Time Frame

The EtG test is quite sensitive and can detect even low levels of alcohol. In fact, the test can detect alcohol in the urine up to five days after consumption.

In studies of participants without alcohol-use disorders, EtG has been detected in urine samples for up to 80 hours (3.3 days) after heavy alcohol exposure.

Limitations

A problem with the EtG test is that it can produce a positive test from the mere exposure to alcohol that's present in many daily use products. Examples of environmental or home products that contain alcohol include:

Foods prepared with or flavored with alcohol
Cleaning products
Mouthwashes
Breath sprays
Hand sanitizers
Hygiene products like antiperspirant
Aftershave
Cosmetics
Hair dye

The reality is that there are hundreds of household products that contain ethanol, according to the National Library of Health's Household Products Database, and exposure to them could possibly lead to a false positive on the EtG test.

Interpreting Results

The following cutoff values have been proposed:

"High" positive EtG test (for example, >1,000ng/mL) may indicate:

Heavy drinking on the same day or the previous day
Light drinking on the same day as the test

"Low" positive EtG test (for example, 500 to 1,000ng/mL) may indicate:

Heavy drinking within the last one to three days
Light drinking within the last 24 hours
Recent intense exposure to environmental products containing alcohol (within the last 24 hours)

"Very low" positive EtG test (for example, 100 to 500 ng/mL) may indicate:

Heavy drinking within the last one to three days
Light drinking within the last 12 to 36 hours
Recent exposure to environmental products containing alcohol

SAMHSA lists EtG as a test that can help both rule in or rule out whether someone has been drinking with high accuracy.

The EtG test accurately detects a person who recently consumed alcohol 70 percent or more of the time. One study showed that for moderate to heavy drinking, this number jumps to 85 percent.

A Word From Verywell

All in all, the EtG test is considered a highly useful test for detecting recent alcohol consumption. But like any test, there is the possibility for a false positive. This is why a positive test should be confirmed either with another test or with verification from the person that he or she did indeed drink alcohol.

Hopefully, as the research on EtG and other alcohol biomarkers unfold, there will be increasingly accurate ways to distinguish between true alcohol use and exposure to alcohol in environmental products.