EtG Test for Confirming Alcohol Abstinence

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.

Why EtG Is Used

The test for EtG is widely used to detect alcohol abstinence in situations that do not allow drinking. These may include:

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

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.

Test Accuracy

There are some limitations to this test. 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:

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

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.

But 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.

Interpreting Results

The following cutoff values have been proposed for test results.

High Positive

A "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

A "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

"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

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.