Urine Testing
When a person is arrested for a DUI, a chemical test is required to measure the alcohol content in the blood (BAC). The three chemical tests available are: blood, breath, or urine testing. Urine testing refers to the chemical examination of the urine in the detection of drugs or alcohol. Urine testing is generally only given as an option where a person is arrested of driving under the influence of drugs, driving under the influence of alcohol and drugs, but not for merely driving under the influence of alcohol. However, urine tests are given when breath or blood are not available. Urine testing has a wide array of problems and legal challenges because urine tests are generally thought of as the least reliable of the three types of chemical tests available. Even thought the tests are scientifically based, they are all prone to human error and require strict procedures to be followed. Police and technicians routinely fail to follow the required procedures, making test results unreliable.
California Vehicle Code Section 23158 states: "If the test given under Section 23612 (Implied Consent provision) is a chemical test of urine, the person tested shall be given such privacy in the taking of the urine specimen as will ensure the accuracy of the specimen and, at the same time, maintain the dignity of the individual involved."
When the urine test is given, the person is advised to void their bladder, wait 20 minutes and go again. The reality is that this is the least reliable method of chemical testing because of the higher results due to having water levels tested instead of direct blood levels. Water levels are in the system over a longer period of time in the body. And therefore the results 'usually' reflect alcohol that has been in the 'water' levels over a longer period of time, when compared to blood levels. The concentration of alcohol in the urine is approximately 1.33 times the concentration of alcohol in the blood at the same time.
As for drugs, urine tests cannot determine when a drug was used. They can only detect the "metabolites," or inactive leftover traces of previously ingested substances. For example, an employee who smokes marijuana on a Saturday night may test positive the following Wednesday, long after the drug has ceased to have any effect. In that case, what the employee did on Saturday has nothing to do with his or her fitness to work on Wednesday. At the same time, a worker can snort cocaine on the way to work and test negative that same morning. That is because the cocaine has not yet been metabolized and will, therefore, not show up in the person's urine.
A survey by the National Institute of Drug Abuse, a government agency, found that 20 percent of the labs surveyed mistakenly reported the presence of illegal drugs in drug-free urine samples. Unreliability also stems from the tendency of drug screens to confuse similar chemical compounds. For example, codeine and Vicks Formula 44-M have been
known to produce positive results for heroin, Advil for marijuana, and Nyquil for amphetamines.
