Law enforcement agencies in New Jersey may turn to urine tests only when other toxicology tests are unavailable. This is because urine testing is considered intrusive, and it cannot be performed in the field by police officers. The results of urine tests may also be misleading. The BAC levels revealed by urine tests are sometimes much higher or lower than actual alcohol levels in the body. This is because alcohol may go undetected in urine for up to two hours and remains in the system for as long as 24 hours.
The results of urine tests may also be unreliable if the sample used is mishandled by laboratory staff or contaminated prior to the test being performed. Many laboratories check the temperature of a urine sample before testing it, but it is not always possible to establish that a sample has not been interfered with. For these reasons, most law enforcement agencies around the country prefer to establish BAC levels using breath or blood tests.
The ethyl glucuronide urine test is becoming more popular because even recent alcohol consumption can be detected. However, while EtG may be detectible immediately after alcohol has been ingested, the metabolite may also lead to a false positive result according to the Substance Abuse and Mental Health Services Administration. The metabolite may also remain detectable in urine for up to 80 hours after drinking has ceased.
The results of toxicology tests are often the most important components of drunk driving cases, and criminal defense attorneys may scrutinize them closely. Even blood and breath test results could be unreliable if the sophisticated equipment involved is not properly maintained and regularly calibrated, and certain medical conditions may lead to misleading results even when the tests are performed correctly.