Urine tests are an easy alternative to the onsite breathalyzer test. Although they are considered an intrusive method (similar to alcohol blood sampling), urine tests are inexpensive and can accurately detect alcohol content in the body.
Although urine samples cannot take place onsite, the officer can request a sample be obtained at a police station, the subject’s home, or at a clinic or hospital. However, lab verification is required for accurate results.
Like all chemical sobriety testing, the urine sample can be affected by the lapse of time between the drinking and the test. Abstaining from drinking before the sample is taken can alter the urine test as the body continues to absorb and break down the alcohol molecules. In addition, alcohol can take up to two hours to show up in a person’s urine. Therefore, a positive urine test doesn’t always mean that the subject was under the influence at the time of the incident.
Through recent technology, scientists have discovered a way to more accurately determine recent (within the last few hours) alcohol consumption as opposed to alcohol ingested over the last several hours or days. Ethyl glucornide (EtG), a direct metabolite of alcohol, will appear in the urine immediately following alcohol consumption. Therefore, its presence in the urine is capable of determining recent consumption even if there’s no measurable alcohol present in the system.
In addition to determining a body’s alcohol level, urine tests also offer a wide range of flexibility in testing for different drugs, such as nicotine and marijuana. As with the blood alcohol test, it is very hard to challenge the evidence provided by a urine test in court due to its accuracy.
Unfortunately, urine testing is prone to alteration by the person tested. If unattended during collection, the subject may dilute or possibly substitute the sample. This must be taken into account during analysis. In an effort to detect the validity of urine samples, temperature testing for sample verification is often used. However, adulteration of urine samples remains difficult to prove.