"The Role of Biomarkers in the Treatment of Alcohol Use Disorders", September 2006, Substance Abuse and Mental Health Services Administration
Widely-Use EtG Test for Alcohol Unreliable
Cannot Distinguish Between Consumption and Exposure
Updated December 31, 2008
A widely-used urine test, utilized by drug-testing laboratories to detect alcohol consumption, may be too inaccurate to be reliable, according to an advisory issued by the Substance Abuse and Mental Health Services Administration.
The EtG (Ethyl Glucuronide) test, which has recently come into popular use by many laboratories, is too sensitive to distinguish between actual alcohol consumption and exposure to small amounts of alcohol found in many household and personal hygiene products, the advisory said.
What Is a EtG Test?
The EtG test is a biomarker test that detects the presence of ethyl glucuronide in urine samples. Usually, it is used to monitor alcohol consumption in individuals who are legally prohibited from drinking alcohol by the justice system or restricted from drinking by their employers.
The EtG test is just one of many biomarker tests available to confirm the presence of alcohol in urine samples. These tests are used to document abstinence and detect relapse, but they can also be used in clinical settings to screen for drinking problems, evaluate interventions for alcohol problems and motivate changes in drinking behavior.
The Problem With the EtG Test
The EtG test is sensitive to the presence of any alcohol, even low-levels, and can detect alcohol in the urine several days after consumption. But the test is so sensitive, it can produce a positive test for ethyl glucoronide from the mere exposure to alcohol that is present in many daily use products.
The EtG test came under scrutiny when a significant number of people, who insisted they had abstained from drinking alcohol, failed the test. SAMHSA used many of those protested cases to research the accuracy of the EtG test and determine the cause of the false positives.
What Causes False Positives?
According to SAMHSA's research, positive EtG tests can result from the use of hand sanitizers, medications, hygiene products, cosmetics, foods and other products that contain even small levels of alcohol. People can test positive for alcohol consumption after being exposed to laundry detergent, antiperspirant, aftershave and even hair spray.
There are hundreds of household products that contain ethanol, according to the National Library of Health's Household Products Database, which could possibly cause a false positive with the EtG urine test.
The advisory also said that gender, age, or ethnicity may also affect EtG test results, but more research is needed to find out for sure.
Where It Stands Now
The EtG test is simply not reliable by itself to determine alcohol consumption. According to the SAMHSA advisory:
"Currently, the use of an EtG test in determining abstinence lacks sufficient proven specificity for use as primary or sole evidence that an individual prohibited from drinking, in a criminal justice or a regulatory compliance context, has truly been drinking.
"Legal or disciplinary action based solely on a positive EtG ... is inappropriate and scientifically unsupportable at this time. These tests should currently be considered as potential valuable clinical tools, but their use in forensic settings is premature."
SAMHSA recommends that biomarker tests be used as a tool to launch a more extensive investigation into possible alcohol use, but not as a stand-alone confirmation.
thank you for your reply. I am familiar with that information, My question is whether, with the values being that high, if there could be anything else other than drinking that could cause those results. My understanding is that incidental exposure usually produces values no higher than 1000. If there is agent of incidental exposure that could produce value of 6000 I'd be interested to know.
With the EtG testing the following have to be taken into consideration:
There is no cutoff known that distinguishes between incidental exposure and drinking alcohol. There is no known level of EtG, or which if exceeded, proves drinking. It is logical to assume that higher levels are more likely to be from drinking but there is no "bright line" that can distinguish between drinking and incidental exposure.
There are also some others things that need to be taken into consideration when looking at the values of EtG:
These include concentration of the urine sample. In patients who are dehydrated or in cases where the sample has been allowed to sit and evaporate, the level of EtG may be artificially higher.
The levels of EtG must be adjusted according to the urine creatine level.
In cases where there is bacteria in the sample, EtG has been noted to be produced by the bacteria.
Certain fermented foods can cause an elevation of EtG, so the patient should be fasting (except for water) for at least 12 hours before the test.
The levels of EtG produced by patients can vary significantly between patients and within a single patient. There have not been any tests with very large numbers of subjects, to be able to narrow down the best level for determination of EtOH consumption.
And, of course, the use of alcohol based skin creams, sanitizers, etc has to be limited.
So, when level of EtG are above 20,000ng/ml, it is usually considered to be EtOH consumption, without too much of a doubt. Levels of 500 to 1000ng/ml are usually dismissed as probably being from incidental exposure.
A level of 6689ng/ml, with a creatine level of 136mg/dl, is pretty high. The patient would probably have to have an inordinately normally high production of EtG, have a urinary tract infection, have just eaten a lot of fermented food, used a gallon of hand sanitizer, had the sample sit around the lab for a while, and be really dehydrated (creatine level in the thousands). So, its possible, but probably not too likely.
The EtG/EtS test is unreliable and should be summarily disregarded. As Gaelic has noted the test is influenced by incidental exposure, endogenous production, urine concentration and is unstable in sample post-collection.
Add to the foregoing that EtG and EtS synthesis is widely variant between individuals and you are left with meaningless numbers.
You and your wife should insist of the treatment facility that they utilize more stable and predictable testing methods.