The 3 DUI Tests: Breath, Blood and Urine

 

There are three different chemical tests that you may encounter when being pulled over and arrested for a DUI. Breath and blood tests are the most common followed by urine. Whether you have a choice of which test to take depends on which state you were arrested in. There are pros and cons with each test in terms of which will lead to a better outcome for your DUI case.

 

Breath Tests

 

There are two types of breath test. The first is the portable breathalyzer, also known as the Preliminary Alcohol Screen (PAS) test, and the Portable Breath Test (PBT). As the names suggest, these are the mobile tests that the field officer has on the road with him, and are used solely to gain probable cause for your arrest after you have been pulled over. The mobile breath tests are 100% voluntary and so you will want to decline taking one if you have been drinking and are unsure of whether or not you are over the limit. The results of the portable breath tests are not admissible in court as evidence against you, mainly because they have been shown to have a high margin of error.

 

The second type of breath test is back at the station after you have been arrested. This is the stationary breath test, the result of which is admissible in court. The way it works is by detecting levels of alcohol in your breath, and multiplying the amount by 2100 to get your Blood Alcohol Level. This equation is known as the “Partition Ratio” and can vary as much as 30% from between individuals. So the figure 2100 is actually just an average, meaning that the breath test is limited in its accuracy in that it is an indirect method for calculating BAC.

 

False positives can occur with breath tests based on a number of factors including periodontal disease, alcohol-soaked food stuck in between teeth, diabetes, gastro-intestinal issues, and rinsing or spraying with an alcoholic mouthwash a short time before blowing into the device.

 

Despite the issues with breath testing and the Partition Ratio, they have become accepted into statutory law, and so it will be difficult to mount a successful defense attacking these methods, although certainly not impossible.

 

Blood Test

 

The blood test is the most reliable type of test, but as with any test, human error can occur and this leaves the potential for an experienced defense attorney to inquire into the storage of the blood, the chain of custody (who handled the blood), and the practices of the particular lab at which the blood was examined.

 

While blood testing is the most invasive form of alcohol and drug testing, many states have made it legal for a police officer to draw your blood without your consent if he has probable cause. In other states, the officer can obtain a search warrant from a judge which entitles him to take your blood without your consent. And in other states, you may face up to a year’s automatic suspension of your driver’s license if you do not agree to give blood.

 

Many lawyers recommend that after being released from the station you go immediately to a hospital or urgent care to have blood drawn and tested independently. If the results are inconsistent with the original blood draw (after factoring in time elapsed) this can give the lawyer something concrete to work with in terms of defending your case.

 

Urine Test

 

The urine test is the least common type of test for detecting alcohol content as it can be quite unreliable. This is because of the errors that can occur during testing and the collection procedures. Generally it is only requested when you have been arrested on suspicion of driving under the influence of drugs (DUID). However, in many states, the urine test is not available to you as an option at all.

 

Ultimately, it may or may not be up to you which test you end up taking. It’s likely that you will be unsure which test to take, and whether it is in your best interest to take the test at all. The best thing to do if you are unsure is to carry the number of an experienced DUI attorney with you who has a 24 hour hotline so that you can exercise your right to contact a lawyer before taking any test. In most states, the amount of time you have to do so is 20-30 minutes, so you want to be able to jump on the phone as fast as possible rather than rifling through the Yellow Pages at the station in a desperate panic.