Chemical Testing

There are three types of chemical tests performed for DUIs. These are breath analysis, urine tests, and blood tests. Usually, field sobriety tests are administered first, and then, if they provide a reason to think that the driver is drunk, a chemical test will be administered. The field sobriety tests tend to be more subjective tests. The chemical tests are considered more accurate. However, sometimes it is possible to challenge chemical testing. If you have been subjected to chemical testing in connection with an Arizona DUI, you should consult Phoenix DUI lawyer James E. Novak.

When you drink alcohol, it comes into your bloodstream. Your body will try to remove it through excretion, evaporation, and your metabolism. How much alcohol you have in your body at a specific time may be measured through chemical testing: breath testing, urine testing, or blood testing.

Breath analysis is one form of chemical testing. It is usually determined by using a portable Breathalyzer that will use breath to measure the concentration of alcohol in your blood by approximating how much alcohol is on your breath through a formula. Urine samples may also be analyzed to decide what your blood alcohol content is. It may take 2 hours from the time of consumption for alcohol to appear in your urine. Like the Breathalyzer, this test indirectly measures blood alcohol concentration by estimating how much alcohol is in the urine. A blood test analyzes blood drawn directly from you. Usually, your blood alcohol level is highest about an hour after you drink. It is easy to measure blood alcohol level by simply conducting a blood test.

There are different state standards, but in Arizona, as in most states, a blood alcohol content of .08 is considered the legal limit. You are considered per se drunk driving if you drive a car while your blood alcohol content is at this level or higher. Chemical testing is used to provide direct evidence in a criminal prosecution that your BAC was above or at the legal limit.

However, you should not necessarily despair about the results of chemical testing. There are multiple factors that can suggest that chemical test results were not accurate. Blood samples may be affected by the type of medication that someone is taking. For example, if someone is taking cough syrup, it could influence alcohol levels. Sometimes cell phone interference can affect the BAC level resulting from a Breathalyzer. In some cases, a urine sample taken two hours after a drunk driving arrest has been taken too late to accurately estimate what the blood alcohol concentration was during the drunk driving.

Under Arizona law, you are required to undergo chemical testing if you are arrested for a DUI. The implied consent law states that if you have been legally arrested by an officer with a reasonable basis to think that you were drunk driving, you have implicitly consented to chemical testing to determine what your blood alcohol content was. This test is supposed to be administered within 2 hours of the drunk driving, and you do not get to choose which form of chemical testing will be administered. Modern breathalyzers are fairly accurate. However, they are not perfect, and not following proper procedures when using a breathalyzer can lead to significant errors. Sometimes the results can be off by .01%.

Moreover, sometimes breath samples are tainted. They are supposed to measure alcohol levels from the vapor in people's lungs, but no alcohol is supposed to remain in the person's mouth. To ensure that it does not, the driver is supposed to be watched for 15-20 minutes before the breath test is administered. If an officer does not ensure accuracy in this way, it may be possible for your attorney to challenge the results.

If you refuse testing after being arrested, the officer may make you give up your license and will report that you refused. The State of Arizona can suspend your license for a year, assuming that it is your first time refusing.

You should take seriously any Arizona charges arising from a suspected DUI. James E. Novak is a former prosecutor who now serves as a defense attorney in the Phoenix area, including for people in Mesa, Tempe, Chandler, Gilbert, Scottsdale, and other cities in Maricopa County. Contact James Novak at (480) 413-1499 or via our online form.