Tests for alcohol often detect the substance's presence in urine for 72 hours or more if the test subject drank heavily. Alcohol is detectable in urine for up to 48 hours if the test subject has consumed three drinks or fewer, according to the Medical University of South Carolina Institute of Psychiatry.
The by-product that indicates the presence of alcohol is ethylglucuronide (EtG). The Medical University of South Carolina Institute of Psychiatry reports that EtG remains in the urine much longer than alcohol remains in the bloodstream or on the breath.
Nevertheless, police testing for alcohol consumption prefer to test breath and blood over urine when screening a drunk driving suspect, as do employers when testing a current or prospective employee. As employee screening company Verification reports, this is because it is much easier to determine a person's level of impairment through breath and blood specimens. Alcohol often pools and remains in the bladder for many hours after it has been metabolized from the bloodstream.
MDHealth.com indicates the majority of alcohol is broken down through the metabolism. The rate at which alcohol is broken down depends on a variety of factors, including a person's weight, overall physical size, gender and even ethnicity.