Understanding The Flow of a DUI Urine Test

 

Police typically use various tests to confirm their suspicion of DUI / DWI. The DUI tests are designed to determine the suspect's blood alcohol content also referred to as BAC. There are currently three different tests that utilize chemicals to measure the BAC. The three tests are either urine based, blood based or breath based. Of the three the urine test has the worst reliability record, and consequently, isn’t used very often.

 

Basics of Urine Testing

 

Oftentimes cops will use a urine test (urinalysis) if they suspect that the driver may be under the influence of drugs in addition to alcohol. Other times a urine sample may be requested if a blood or breath test is not readily available.

 

When the test is administered the suspect is supposed to be provided sufficient privacy in order to keep the person's dignity intact. At the same time police are required to make sure the sample comes from the individual and that there is no tampering with the sample. The normal procedure will ask the suspect to drain their bladder completely and repeat the process in 20 minutes.

 

Problems with Testing

 

The primary problem with urine testing in drunk driving cases lies within the water content of urine. Alcohol is normally present in water at a much higher rate than in the blood. Because of this higher occurrence a urine test will usually result in a person being convicted of DUI even though their actual BAC is within legal limits.

 

When used to determine if a person is guilty of driving under the influence of drugs the urine test is equally problematic. Various drugs and legal products remain in the urine much longer than their affect. Marijuana is known to show up in a urine test three days after the drug has been used and for heavy users, it can show up in urine for up to 3 months! How would you like to be arrested for drugged driving if you haven’t smoked in a month?

 

Scientific Evidence of Problems

 

The National Institute of Drug Abuse conducted a study of urine tests to determine their accuracy. In their study they found that 1 in 5 testing labs incorrectly reported the presence of illegal drugs in urine samples. That’s a 20% error rate – a SERIOUSLY high rate. In addition the drug screening is not able to distinguish between similar substances. A non-narcotic type of cough syrup has been routinely shown to reflect that the suspect was using heroin. Another common product, Advil, shows a test result that is positive for marijuana.

 

Problems with Administering the Test

 

Not all of the problems with the urine tests lie within science. Since these tests have strict guidelines that must be followed perfectly, there is a lot of room for human error.

 

For instance, the presence of glucose can alter the results of the test. Most urine test kits provide a supposed that is supposed to remove the glucose from the urine. If this powder is not used then the BAC will show higher that it really is.

 

Storage of the sample is another issue. Urine samples should be stored at cool temperatures in order to lessen fermentation. Fermentation will take chemicals normally found in the body and actually produce alcohol. If the sample is not stored correctly the BAC of the sample will actually increase from the time of collection to the time of independent testing.

 

Going back to the earlier information about the amount of alcohol present in urine compared to the alcohol in blood, many labs will use a math formula to determine the correct BAC. However, since these formulas are elementary in nature, they are done by hand rather than a computer. That lends itself to yet another chance for someone to make a mistake.

 

The entire process of collecting, documenting, transferring, and testing urine or other evidence is known as the chain of custody, and this is an important consideration in finding errors in the process that a good DUI defense lawyer can use to get your case reduced or dismissed or evidence such as a urine test unusable by a prosecutor.

 

Defending Against DUI Urine test

 

Some DUI attorneys feel very comfortable defending their client against a DUI conviction that involves a urine test. The substantial amount of scientific data that proves the unreliability of urine tests is usually the starting point for the lawyer. If the procedures for collecting the sample were followed properly then the attorney will request that the sample be tested again with an independent lab. If the sample was improperly stored, or destroyed, then it may be possible to dismiss the case by declaring the test invalid. Talking to an attorney that specializes in DUI cases is the best course of action for anyone facing a drugged driving (DUID) charge.