Ethyl glucuronide (EtG) is a direct metabolite of beverage alcohol (ethanol). Its presence in urine may be used to detect recent alcohol consumption, even after ethanol is no longer measurable. The presence of EtG in urine is a definitive indicator that alcohol was ingested.

Key benefits of using an EtG test include:

• Detects recent usage more accurately and for a longer period of time than standard testing
• Ideal for zero tolerance and abstinence situations
• Strong indicator of alcohol ingestion within the previous 3 to 4 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
• Tests are performed by LC/MS/MS on state of the art equipment for accuracy and reliability
• EtG may be run on urine specimens in conjunction with other drug testing panels
• Expert witness and affidavit services available

Traditional laboratory methods detect the actual alcohol in the body, which reflects current use within the past few hours (depending on how much is consumed). The presence of EtG in urine indicates that ethanol was ingested within the previous 3 to 4 days, or approximately 80 hours after ethanol is eliminated from the body. Therefore, EtG is a more accurate indicator of the recent ingestion of alcohol than measuring for the presence of ethanol itself.

EtG is a direct metabolite of alcohol (ethanol), and its detection in urine is highly specific, similar to testing for other drugs. Add to this, Our preferred lab utilizes some of the most sophisticated, sensitive, and specific equipment and technology available, LC/MS/MS, to screen, confirm, and quantitate EtG. This methodology provides highly accurate results. As is the case with any laboratory test, it is also very important to obtain clinical correlation.

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.

Studies show that EtG is stable in urine for more than 4 days at room temperature. Recent experiments indicate that heating urine to 100?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.

Methods to detect EtG include immunoassay (EIA or ELISA), gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), and liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Immunoassay methods are of limited specificity and sensitivity with a limit of detection of approximately 1000 ng/mL. GC/MS and LC/MS methods are much more specific than immunoassay, and offer detection limits of approximately 500 ng/mL.

LC/MS/MS methods utilize the most technologically advanced instrumentation currently available in forensic and clinical toxicology and provide the highest sensitivity. Redwood utilizes an LC/MS/MS instrument for the confirmation of EtG, which has a limit of detection below 100 ng/mL.

Various cutoff levels (100, 250, 500, or 1000 ng/mL) are suggested for use in EtG testing. Any EtG level over 100 ng/mL indicates exposure to ethanol. In order to provide alcohol abstinence programs with the most clinically relevant answer to whether or not recent alcohol consumption has occurred, using a 100 ng/mL cutoff for EtG detection is the best and most definitive test available to answer this question. Our preferred lab uses a 100 ng/mL cut-off level.

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 (>.04 gm %) in the urine, and EtG is also detected in excess of 100 ng/mL, then this is very strong evidence that beverage alcohol was consumed.

Most alcohol abstinence programs require an agreement to avoid all products containing alcohol, including; mouthwash, Nyquil®, OTC medications, etc. Consumption of these products could produce a positive test for alcohol and/or EtG and would thus violate the agreement.

What does a positive EtG test above 100 ng/mL mean?

A positive EtG test above 100 ng/mL indicates the definitive recent ingestion of alcohol. The only way you can have EtG in the urine is if alcohol is in your body. In addition, using a 100 ng/mL cutoff nearly doubles the time of detection of recent alcohol detection versus the use of a 250 ng/mL cutoff. In summary, the 100 ng/mL EtG cutoff is superior for monitoring purposes, and provides the most sensitive and definitive indicator of recent alcohol ingestion.