Alcohol is rapidly eliminated from the body at a rate of approximately one drink per hour. Whether looking for alcohol in breath, blood, saliva or urine, using the standard technology, the rapid elimination limits the detection of alcohol to a matter of hours.
For example an individual who was “under the influence” of alcohol using standard technologies (breath, blood or saliva > 0.08%) at 10 PM would likely test negative the next morning at 9 AM due to the rapid elimination of alcohol from the body.
After years of research, Ethyl Glucuronide (EtG) was found to be a direct metabolite of the alcohol (ethanol). EtG has emerged as the marker of choice for alcohol and due to the advances in technologies is now routinely available. Its presence in urine may be used to detect recent alcohol consumption, even after ethanol is no longer measurable using the older methods. The presence of EtG in urine is a definitive indicator that alcohol was ingested. Other types of alcohol, such a stearyl, acetyl and dodecanol, metabolizes differently and will not cause a positive result on an EtG test.
The EtG test has become known as the “80 hour test” for detecting any amount of consumed ethyl alcohol. This is not totally true. It is true that EtG can be detected in chronic drinkers for 80 hours or even up to 5 days. During this period of chronic use, the EtG level can exceed 100,000 ng/mL. Two primary factors to determine the window of detection is based on volume of alcohol consumed and the time between each drink. A person that consumes 3 drinks can only have a detectable level of EtG for approximately 20 to 24 hours and peaks at approximately 9 hours with an EtG level around 15,000 ng/mL.
Therefore, the presence of EtG in urine indicates that ethanol was ingested. EtG is a more accurate indicator of recent consumption of alcohol than measuring for the presence of ethanol itself.
EtG is stable in urine for more than 4 days at room temperature. Recent experiments indicate that heating urine to 100 degrees C actually increased the stability of EtG. Therefore, heat does not cause the breakdown of EtG, it actually increases stability. In addition, no artificial formation of EtG was found to occur following the prolonged storage of urine at room temperature fortified with 1% ethanol.
EtG is a direct metabolite of alcohol (ethanol), and its detection in urine is highly specific, similar to testing for other drugs. The typical lab utilizes the most sophisticated, sensitive, and specific equipment and technology available, LC/MS/MS, to screen, confirm, and quantitative EtG. This methodology provides highly accurate results.
Studies indicate that alcoholics in abstinence have no detectable levels of EtG in their urine after approximately 80 hours of detoxification.
EtG is only detected in urine when alcohol is consumed. This is important since it is possible to have alcohol in urine without drinking. Alcohol in urine without drinking is due to the production of ethanol in vitro. Ethanol in vitro is spontaneously produced in the bladder or the specimen container itself, due to fermentation of urine samples containing sugars (diabetes) and yeast or bacteria. Since the ethanol produced is not metabolized by the liver, EtG will not be produced and will therefore not be detected in a urine containing alcohol as a result of fermentation.
Tests show that “incidental exposure” to the chronic use of food products (vanilla extract), hygiene products, mouthwash, or OTC medications (cough syrups) can produce EtG concentrations in excess of 100 ng/mL. However, if measurable ethanol is detected (greater than .04 gm%) in the urine, and EtG is also detected in excess of 250 ng/mL, then this is very strong evidence that beverage alcohol was consumed.
Labs will allow you to select 100, 250 or 500 ng/mL as the cutoff level. It is strongly recommended that only the 500 ng/mL level be used. This avoids and eliminates any claim by the donor that the positive EtG test is a result of incidental or unintentional exposure. All testing performed on products or foods classified as incidental or unintentional exposure has never produced a positive EtG level greater than 500 ng/mL.
The benefits of an EtG urine test includes:
- Detects recent usage more accurately and for a longer period of time than standard testing
- No false positives
- No EtG found in non-drinkers
- Ideal for zero tolerance and abstinence situations
- Strong indicator of alcohol ingestion within the previous 3 to 5 days
- EtG is only evident when alcohol is consumed and is not produced as a result of fermentation
- Allows monitoring in alcohol treatment programs
- Acts as an early warning system to detect trends towards relapse