There are three types of tests used to determine blood alcohol level, or blood alcohol concentration (BAC). In some states, but not all, drivers will be allowed to choose which test they would like to take. Moreover, some parts of the country do not offer all three tests. The tests are:

  • The Breath Test: This test is the most common, and measures blood alcohol by having the suspect breathe into a machine. These tests rely on how much alcohol is absorbed into sacs in the lungs, and are highly inaccurate because it they may actually measure alcohol residue in the mouth, esophagus, or digestive system, rather than the blood. Also, bodily functions or using mouthwash, breath spray, or eating a breath mint can skew the results. Thus, the breath test really only measures the presence of alcohol in the system, and does not necessarily produce an accurate figure of how much.
  • The Blood Test: This test is the most accurate test. It is highly specific and measures the presence of alcohol and drugs in your blood. It requires the police to draw a sample of blood for testing.
  • The Urine Test: This test is the least accurate and the least reliable. The time between a person’s last drink and when they were tested can have a significant impact on the test. This test also measures the presence drugs as well as alcohol. However, some departments have stopped using the urine test because of how inaccurate it is.

Pros and Cons: Which Test Should I Take?

If given the option of choosing which test to take, it is important to remember that the blood test is the most accurate. Because it is the most accurate and precise, it will also show the presence of any other substances in the body. Thus, submitting to a blood test may result in exposing the person being tested to more criminal liability. Dually, it may demonstrate that there is absolutely nothing in the driver’s system.

As far as other tests are concerned, the breath test and urine tests are considerably less accurate. Therefore, even if you are sure you are not over the legal limit, the breath test and urine test are so variable that they might indicate otherwise. This also makes the breath test and urine test more susceptible to challenges in court.

How Are Chemical Tests Different from Field Sobriety Tests?

If you are pulled over on suspicion of drunk driving, the officer will usually first ask you to submit to a field sobriety test, which usually requires:

  • Reciting the alphabet backwards
  • Walking in a line
  • Moving a finger-to-nose test
  • Following a light or pen with your eyes

These tests are voluntary and you do not have to submit to them.  In fact, studies have shown these field sobriety tests are designed to make you fail and so provide more evidence for the officer to arrest you for drunk driving. However, be aware that in some states, refusing to submit to a handheld breathalyzer can result in an automatic, temporary suspension of your license.

Can I Refuse to Take a DUI or DWI Test?

If you are arrested for a DUI or DWI, the police will ask you to submit to a test to determine your blood alcohol level. While you can refuse many these tests in some places, sometimes a refusal can have serious consequences. In a small number of places, the police can physically restrain you to draw blood. It is more common for a refusal to result in your license being automatically suspended for a certain periods of time. In some places, the prosecutor may be able to introduce your refusal at trial as evidence.

Do I Need a Lawyer?

If you have been arrested for DUI or DWI, you should consult a DUI/DWI lawyer immediately to learn about your rights and defenses. Contacting an attorney near you immediately, even before submitting to a DUI test, can help you make the right decisions that will effect your case, and therefore your life, in the long run.