Do you need to test someone to see if they are abstaining from alcohol? The ethyl glucuronide (EtG) test is often used to see if a person has been drinking. EtG is produced in the body when a person is exposed to ethanol, which happens when someone drinks alcohol.
After having alcohol, only a small amount is eliminated from your body by urinating. As the body takes in and breaks down alcohol, EtG is formed. It can be found in a person’s urine, hair, nails, or blood. However, testing urine is the most commonly used way to look for EtG. A test can find EtG in urine for up to five days after a person consumes alcohol.
In contrast, using a breath test to detect alcohol only shows alcohol consumed in the last several hours. A breath test is mainly useful to show how intoxicated a person is, rather than how often a person drinks. Another way to check a person’s alcohol intake is by using a transdermal alcohol monitor. However, this type of device is costly and inconvenient to use.
Why would you need to administer an EtG test?
Sometimes it’s important to know that a person is abstaining from alcohol if drinking is not allowed in certain situations, including:
- Jobs such as an airline pilot, doctor, attorney, and other professionals when being sober is very important and they could even put another person’s life at risk if they were impaired.
- A person who is on probation.
- Court cases when showing sobriety is required.
- Person who needs a liver transplant.
- At a school.
- A program for those who were driving under the influence (DUI).
- Program that treats alcoholism, such as an addiction treatment center or facility.
Drinking too much is one of the most common types of substance abuse in the United States. For example, according to a 2015 National Survey in Drug Use and Health, nearly 27% of those over 18 said they engaged in binge drinking in the previous month and 7% said they were involved with heavy alcohol use in the last month. Binge drinking is defined as a man having five or more drinks and a woman having at least four drinks at the same time or within a couple of hours on at least a single day in the past month. This definition is from the Substance Abuse and Mental Health Services Administration.
What do the test results mean?
According to a study published by the Drug and Alcohol Dependence Journal, the EtG test can detect light and heavy drinking within a certain number of days. The results depend on what level of EtG, or “cutoff,” is used.
For example, a “low” positive EtG test result of 100 ng/mL found:
- 84% of light drinking for one day
- 76% of light drinking for two days
- 79% of light drinking for five days
If the cutoff is 500 ng/mL of EtG, testing could find:
- 78% of heavy drinking for one day
- 71% of heaving drinking for two days
- 59% of heavy drinking for five days
So these results show that if the lower cutoff level of 100 ng/mL of EtG is used, alcohol use can be more accurately detected two or more days after a person consumes alcohol. According to the study, the 500 ng/mL cutoff was less likely to show a false positive test result for drinking. However, using the higher 500 ng/mL cutoff could result in missing a person’s use of alcohol.
What are the different types of EtG testing?
EtG can be detected by using a standard immunoassay test with a urine sample that’s quick and not too expensive. Another type of test uses mass spectrometry and must be done at a drug testing laboratory.
One study showed that results from both types of tests were often the same and equally effective at finding EtG. The standard immunoassay test was done at an outpatient addiction clinic, while the test using mass spectrometry was conducted at a laboratory certified for drug testing.
Are there any limitations of EtG testing?
EtG testing does not show if a person is impaired from drinking. Also, using certain products with alcohol can cause a positive result in an ETG test. This includes:
- Certain cosmetics
- Hand sanitizers
- Breath spray
These are just a few examples of products with ethanol that can cause a person to falsely test positive on an EtG test.