Ethyl glucuronide (EtG) Testing in Urine: What You Should Know

EtG is a byproduct of both ethanol (the alcohol consumed) and glucuronide, a common biological component produced in the liver that binds to numerous poisons and medications in the body, allowing them to be expelled in the urine. When someone consumes alcohol, even in little amounts, EtG is produced and can be identified in the urine of the individual.

What is the purpose of EtG?

The EtG test is extensively used to determine alcohol abstinence in settings where it is not permitted to consume alcoholic beverages. The following are examples:

• Alcohol treatment programs 1

• Disputes in the courts (for example, child custody)

• DUI or DWI education and training

• Patients undergoing liver transplantation2

• Probation and parole programs

• Educational institutions or the military

Please keep in mind that the EtG test is not recommended for use in workplace testing programs because it does not assess current alcohol-related impairment.

What makes urine EtG detection superior to a blood or breath alcohol test is that it is noninvasive.

EtG may be detected in the urine for a significantly longer period than alcohol can be detected in the blood or breath. Even after a few drinks, EtG can be detected in the urine for up to 60 hours, and in some cases, for up to 84 hours or longer if the drinking is more intense.

Is it possible to determine how much alcohol someone has consumed (i.e., the number of drinks) based on the EtG Amount?

No, not at all. Higher levels of EtG are thought to be associated with higher levels of alcohol use; however, the actual figure is impacted by a variety of factors, including the amount of alcohol ingested and when it was consumed. The longer the period between consumption and measurement, the lower the EtG level. Additionally, some persons may metabolize more alcohol into EtG than others and/or excrete it at a faster rate than others. In addition, because there is a limit to the quantity of EtG that can be measured, drinking exceeding that limit may not elevate EtG levels any higher than what can be detected (ceiling effect). Instead of detecting heavy drinking, it was intended to detect "any alcohol consumption." It is recommended that you order percent dCDT if you want to identify heavy drinking.

Using the results to make inferences: It has been proposed that the following cutoff values be used for test results.

Positivity is soaring.

A “high” positive EtG test result (for example, >1,000ng/mL) may suggest one or more of the following:

• Excessive alcohol consumption on the same day or the day before7

• Only a small amount of alcohol should be consumed on the day of the test.

Positivity is at a minimum.

A “low” positive EtG result (for example, 500 to 1,000ng/mL) may suggest one of the following conditions:

• Excessive use of alcoholic beverages within the previous one to three days

• Only a small amount of alcohol consumed within the previous 24 hours

• Extensive exposure to alcohol-containing environmental pollutants in the recent past (within the last 24 hours)

The negative sentiment is really low.

Positive EtG results that are “very low” (for example, 100 to 500 ng/mL) may indicate:

• Excessive use of alcoholic beverages within the previous one to three days

• Light drinking within the previous 12 to 36 hours is acceptable.

• Recent exposure to alcohol-containing environmental materials (environmental products).

Why do you report EtG levels at two different cut-off levels of 100 ng/ml and 500 ng/ml? What is the difference between the two?

To ensure that you have all the information you need to make an informed clinical decision, we do this. Our test technique can detect EtG at concentrations as low as 100 ng/ml, but we incorporate a "margin of safety" so that at 100 ng/ml, we may be confident that EtG is present, indicating even tiny amounts of drinking. Some findings in the literature and concerns expressed in legal cases have shown that other sources of alcohol (e.g., mouthwash, hand sanitizer) may cause EtG levels in the urine to rise above 100 ng/ml. Even though these events are rare and difficult to recreate under controlled settings, the clinician may choose to apply the 500 ng/ml cut-off in cases where a higher level of assurance is required (forensic cases, for example).