Alcohol (also called ethyl alcohol or ethanol) is one of the most widely abused substances. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are minor ethanol metabolites produced by the liver and direct biomarkers of ethanol exposure. EtG and EtS are highly sensitive, water soluble, nonvolatile metabolites that can be detected at quantifiable levels in hair, urine, oral fluid and blood. Urine, however, is the preferred matrix for testing.

What is Ethyl Glucuronide? Ethyl glucuronide (EtG) is a direct metabolite of ethanol. Its presence in urine can be used to detect recent alcohol exposure, even after ethanol is no longer measurable.

What is Ethyl Sulfate? Ethyl sulfate (EtS) is a specific metabolite of ethanol that is stable in urine and not subject to post-collection synthesis or degradation. 

How reliable is EtG/EtS testing? The presence of both EtG and EtS in body fluids indicates exposure to ethanol and cannot come from exposure to other types of alcohol, such as isopropyl alcohol. 

Incidental exposure from substances containing even small amounts of ethanol, such as OTC medications (cold and cough medicines), food sources (kombucha, sauerkraut, kimchi, alcohol-based flavorings and extracts, dishes cooked with wine or other alcohol, and non-alcoholic beer or wine), mouthwash and breath fresheners, or hand sanitizers could result in low-level positive drug test results for EtG, EtS or ethanol. Excessive use of hand sanitizers, for instance, may cause EtG levels to exceed 500 ng/mL. Patients should be provided with a list of potential sources of ethanol exposure.

How stable is EtG/EtS in a urine specimen? EtG/EtS is stable in a urine specimen for at least seven days at room temperature, one month when refrigerated, and up to 12 months when frozen.

In rare scenarios, EtG can form post-collection. For example, if a person with uncontrolled diabetes has excess glucose in their urine and the sample is exposed to E. coli (from a urinary tract infection, for instance), EtG could be formed in vitro. EtS is not prone to this same phenomenon. 

Can EtG results tell me how much alcohol has been consumed? EtG/EtS production may vary among individuals, and because of the long detection period, estimating the amount of alcohol consumed is not possible. 

Detection Time in Urine: Ethanol testing is limited to <1 day post-consumption. EtG/EtS detection time is 1–3 days.

Detection Time in Oral Fluid: <1 day