How Long Is Alcohol Detectable by Urinalysis?


Urinalysis is a common method for testing urine for signs of substances such as drugs or alcohol. Urinalysis is commonly done in drug treatment centers, but may also be used in places of employment where being under the influence of alcohol during a work shift can put yourself or other at harm. A urinalysis is one of the least intrusive forms of drug testing, but at the same time provides accurate results within a specific time frame.

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Urinalysis tests work by detecting a metabolite of alcohol called ethyl glucuronide (EtG). Ethyl glucuronide appears in the bloodstream and urine after drinking alcohol has been metabolized in the body. EtG can only be present in a urine sample if a person has been drinking. This is an important benefit, as traditional alcohol testing that searches only for traces of ethanol can sometimes bring back a false positive. This occurs when urine in the bladder has elevated sugar levels and interacts with yeast and bacteria. This is referred to as "ethanol in vitro." Since EtG is produced only when ethanol is metabolized by the liver, EtG will be detected only in test subjects who have recently been drinking.


Testing for alcohol is done in much the same way that any urine test is done. The testing subject will be given a sterile cup to urinate in, usually with a temperature strip on the side to insure that the urine is fresh and real. The cup will then be sealed and sent off to a lab to be tested for EtG.


In traditional alcohol testing methods that search for ethanol, alcohol can only be detected for up to three or four hours after consumption (depending on how fast the body can metabolize the ethanol). In EtG detection, alcohol can be tested for up to four days (about 80 hours after ethanol has been completely metabolized by the liver). There is also no worry for alcoholics who have recently detoxed. The test will only show positive if you have consumed alcohol within four days, regardless of how much alcohol you have consumed in the past.


The detection of EtG in urinalysis is just as accurate as detection methods for other types of substances such as illicit drugs. Some oral hygiene products and over-the-counter medications may use alcohol in their active ingredients, and thus will come back with a positive result for alcohol consumption. However, most environments that employ random alcohol testing ask subjects to sign an agreement that they must refrain from using substances that could give a false positive.