Ethyl Glucuronide (EtG) and Urine Testing for Alcohol
"After years of research, Ethyl Glucuronide (EtG) and Ethyl Sulfate (EtS) were found to be a direct metabolite of the alcohol (ethanol). EtG/EtS 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/EtS 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/EtS test.
"The EtG/EtS test has become known as the “80 hour test” for detecting any amount of consumed ethyl alcohol. This is a misnomer. It is true that EtG can be detected in chronic drinkers for 80 hours or even up to 5 days but not from a person that only consumed 2 or 3 drinks. During the period of chronic use, the EtG level can exceed 100,000 ng/mL. A level of 1.25 million was found in one sample. 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. The level peaks at approximately 9 hours with an EtG level around 15,000 ng/mL.
"The presence of EtG and EtS in urine indicates that ethanol was ingested.
"EtG/EtS 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. Therefore, heat does not cause the breakdown of EtG/EtS. In addition, no artificial formation of EtG/EtS was found to occur following the prolonged storage of urine at room temperature fortified with 1% ethanol.
"EtG/EtS 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 quantify EtG/EtS. This methodology provides
highly accurate results.
"EtG/EtS 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/EtS 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/EtS concentrations in excess of 100 ng/mL. However, if EtG is detected in excess of 250 ng/mL, then this is very strong evidence that beverage alcohol was consumed."
Jim Turnage, "Innovations in Substance Abuse Testing (Updated March 2012)," presented for the State Bar of Texas (Dallas, TX: Forensic DNA & Drug Testing Services, Inc., April 26-27, 2012).