Ethylglucuronide (EtG) is a non-volatile, water-soluble, and stable direct metabolite of ethanol (EtOH).   EtG is formed in the liver by conjugation of ethanol with activated glucuronic acid representing about .02-.06 % of total ethanol elimination.  This test is a unique and extremely sensitive indicator of ethanol exposure.  This makes EtG a very reliable indicator of alcohol use. 
 
There is a degree of overlap between positives from intentional consumption and innocent positives from incidental exposure.  Incidental exposure refers to ethanol exposure from sources other than alcoholic beverages. Examples of such products containing ethyl alcohol include some over the counter cough medications (up to 10%), mouth wash or mouth rinse (up to 27% EtOH), food items such as vanilla extract, cooked foods containing ethanol, herbal tinctures, and hand sanitizers (60-80% EtOH).  A positive EtG result from any of these sources does not constitute an analytical false positive, but rather is a TRUE POSITIVE indicating that EtOH has been used in some form.  Individuals in total abstinence or zero-tolerance programs are cautioned about the use of such products and may not be excused if they claim a positive EtG is the result of incidental exposure.

A number of studies have been done to evaluate the effect of EtOH containing products on the production of EtG.  A study was published in the November/December 2006 Journal of Analytical Toxicology (JAT) based on 9 subjects gargling with mouthwash (12% EtOH) for 15 minutes.  A total of 39 specimens were collected; 32 of 39 EtG values were under 200 ng/mL, 5 were between 200 and 250 ng/mL, 3 were between 250 and 300 ng/mL, and one specimen was 345 ng/ml with all peak values occurring at less than 12 hours after exposure.

In a second part of the study, 11 participants gargled 3 times daily for five days.  The first morning void was collected on each day.  16 of the 55 specimens collected had EtG ranging from 50 to 120 ng/mL.  All the rest were negative.   Similarly, another study appearing in JAT was done using Germ X® hand sanitizer.  The sanitizer was used at various frequencies during an 8 hour work day.  The only positive specimen in this study was from a participant who used the sanitizer every 15 minutes during an 8 hour workday, testing at 62 ng/mL.

It is noteworthy that most data gathered to date have shown that low level positive EtG (<500 ng/mL) results can occur following what might be considered excessive (or at least unusual) use of the above listed substances, i.e., use of a hand sanitizer every 4 minutes for an hour in an unventilated area or use of medications in larger or more frequent doses than recommended by the manufacturer

At STERLING we did two small studies involving Nyquil® and Purell® with similar results.  However, we did have a participant in each study that produced a positive result in excess of 500 ng/mL.  The highest value obtained was 766 ng/mL in the Nyquil® Study.  As with every new test, continuing research will better define the appropriate cutoffs to be used in various situations.  Also of note is the fact that none of the specimens in any of the referenced studies contained EtOH above the normal reporting level of 20 mg/dL.

Note:  EtG (Ethylglucuronide) is a sensitive biomarker of ethyl alcohol (EtOH) exposure;
a low-level positive EtG could result from sources other than beverage alcohol.

STERLING has three EtG cutoffs available to select a monitoring level that best fits a client’s program goals.  As with any test used to monitor drug use, using the higher cutoff results in a somewhat shorter window of detection and missed true positives that might have been reported at a lower cutoff.

Following is a list of EtOH containing products and some non-alcoholic alternatives.  This list is representative of available products but is by no means intended to be a complete list of any and all sources of ethanol that might be encountered in every day living.