Ethyl glucuronide (EtG) is a
metabolite
In biochemistry, a metabolite is an intermediate or end product of metabolism.
The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, c ...
of
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
which is formed in the body by
glucuronidation
Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve glycosid ...
following exposure to ethanol, usually from drinking
alcoholic beverage
An alcoholic beverage (also called an alcoholic drink, adult beverage, or a drink) is a drink that contains ethanol, a type of alcohol that acts as a drug and is produced by fermentation of grains, fruits, or other sources of sugar. The c ...
s. It is used as a
biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...
to test for ethanol use and to monitor alcohol abstinence in situations where drinking is prohibited, such as by the military, in alcohol treatment programs, in professional monitoring programs (health professionals, attorneys, airline pilots in recovery from addictions), in schools, liver transplant clinics, or in recovering
alcoholic
Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomin ...
patients.
In addition to its use to monitor abstinence and detect drinking, EtG also has potential for monitoring the amount of alcohol use over time because it can be detected in hair and nails, though the effectiveness of this has not yet been proven.
A disadvantage of the test is that because EtG can be detected in samples at very low levels, it can also be positive after exposure to alcohol from non-beverage sources, or incidental exposure, which can lead to false positives. The sources of possible exposure in the environment are numerous and include alcohol in
mouthwash
Mouthwash, mouth rinse, oral rinse, or mouth bath is a liquid which is held in the mouth passively or swilled around the mouth by contraction of the perioral muscles and/or movement of the head, and may be gargling, gargled, where the head is ti ...
, foods, over-the-counter medications, and even from inhalation of alcohol from topical use. It is impossible with this biomarker to distinguish small amounts of drinking from extraneous exposure to alcohol.
Hair testing controversy
A growing number of articles are documenting the high sensitivity and specificity of hair (or nail) EtG for detection of heavy drinking.
EtG testing in hair specimens was previously attempted by laboratories in the United Kingdom, but has suffered from numerous lawsuits. Due to the concerns of legal risk, few laboratories offer this type of testing anymore, as it has been determined to be unreliable and unsupportable. The Society of Hair Testing (SOHT) also notes the limitations of EtG, stating that this form of testing can determine "chronic excessive alcohol consumption only. This consensus is not applicable for determination of abstinence from alcohol or moderate consumption of alcohol." SOHT also states, "It is not advisable to use the results of the hair testing for alcohol markers in isolation".
The U.S. Substance Abuse and Mental Health Services Administration has cautioned that the test is "scientifically unsupportable as the sole basis for legal or disciplinary action" because the highly sensitive tests "are not able to distinguish between alcohol absorbed into the body from exposure to many common commercial and household products containing alcohol and from the actual consumption of alcohol."
[Center for Substance Abuse Treatment.]
The Role of Biomarkers in the Treatment of Alcohol Use Disorders. Substance Abuse Treatment Advisory
Volume 5, Issue 4, 2006
See also
Other experimental serologic tests (
biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...
s) for recent alcohol use include
5-hydroxytryptophol,
ethyl sulfate
Ethyl sulfate (IUPAC name: ethyl hydrogen sulfate), also known as sulfovinic acid, is an organic chemical compound used as an intermediate in the production of ethanol from ethylene. It is the ethyl ester of sulfuric acid.
History
This substance ...
,
phosphatidyl ethanol,
sialic acid Sialic acids are a class of alpha-keto acid sugars with a nine-carbon backbone.
The term "sialic acid" (from the Greek for saliva, - ''síalon'') was first introduced by Swedish biochemist Gunnar Blix in 1952. The most common member of this gr ...
level,
β-hexosaminidase, mitochondrial
AST levels, and alcohol metabolites such as
erythrocyte
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...
acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the mos ...
and acetaldehyde adducts.
References
{{reflist
Alcohol
Ethyl esters
Glucuronide esters
Recreational drug metabolites