Chemical Tests For DUI

What are 'chemical tests' as they are used in a DUI arrest?

Chemical tests in a DUI arrest would be either a breath test, a blood test or a urine test that a suspect is given following their arrest, which will yield a particular reading as to their BAC level.

What is the 'implied consent law'?

The 'Implied Consent Law', as it applies within a DUI arrest, is essentially the requirement that if you are lawfully arrested for DUI, you must take a chemical test. You must take either a blood test or a breath test, or, if your state offers it, a urine test. And if you fail to do so then you can face significant consequences, including a long term suspension of your drivers license.

When does a motorist have the right to refuse a chemical test during a DUI arrest?

In some states it is optional whether the person who is arrested for DUI takes a blood or breath test. It's voluntary. However, in most states, it's required, and if the person is lawfully arrested and refuses to take a blood or breath or urine test, they can face stiffer consequences as well as a long-term suspension of their driver's license. And, in fact, sometimes there can be a forced blood draw where they're actually restrained and have blood drawn. However, there may be situations where for medical reasons a person doesn't have to take a particular test. For example, a haemophiliac may object to having his blood drawn for medical purposes, and that would be legitimate. However, he would then be asked to take a breath test or a urine test in lieu of the blood test.

What are the known errors associated with DUI breath tests?

There are a number of known errors associated with DUI breath tests. First of all there can be defective equipment, and that is to say, machines sometimes fail. Machines sometimes are inaccurate, and are not maintained properly. These machines are often not calibrated correctly and so there can be defects in the equipment. Secondly, the breath test machine can be improperly administered. If the officer is not trained properly, if the officer does not go through the proper checklist, then the improper administration of the breath test can result in an erroneous reading. And finally, there can be issues with regard to the person taking the breath test. If the person has a fever, if the person has acid reflux, if the person has cavities and alcohol that's trapped in their mouth that gets blown into the device - any of these things can cause there to be a falsely high reading. And all of these are issues that need to be examined anytime somebody is prosecuted for DUI and takes a breath test, because the reading may in fact be erroneous.

Can mouthwash or treatments increase my BAC on a breath test?

Mouthwash, if it is alcohol-based, such as Listerine or Cepacol, can increase your BAC level because it can cause residual alcohol to remain in your mouth and then be blown into the machine. That alcohol is thought to evaporate in about 15 to 20 minutes. That is the reason why, any time a breath test is given, particularly at the side of the road when a person is first detained, it's very important that the police officers wait 15 to 20 minutes before administering a breath test.

What are some scientific errors associated with DUI breath tests?

There are a number of scientific errors associated with breath tests. One is there could be residual alcohol in the throat or the mouth that is blown into the machine that causes a falsely high reading. There can be other chemicals in human breath that can be mistaken for alcohol and cause the machine to render a particular BAC reading when the person has much less alcohol in their breath, or no alcohol in their breath. The machines are not foolproof and oftentimes can register an erroneous of falsely high reading.

How can belching, vomiting, or hiccups affect my BAC?

Belching, vomiting, hiccups, and also acid reflux gurd, can affect your BAC level by causing a falsely high reading. The reason is that the breath machines are designed to measure deep lung alcohol or alcohol from the deep lung tissue, that is to say alcohol that's been digested, absorbed and delivered into the deep lung tissue. However, when we burp and we belch, when we hiccup, if we have acid reflux what happens is semi digested alcohol can be regurgitated from the stomach into the throat and blown into the breath machine, and as a result it is measuring mouth alcohol at a much higher concentration, as opposed to deep lung tissue alcohol, which is thought to correlate to blood alcohol level. So somebody in this situation could blow a .15 BAC for example, when their true blood alcohol level is only a .05.

What is the margin of error for chemical DUI tests?

The margin of error on a blood test is thought to be .005, so if a blood test comes back let's say .08 that would presumably mean that range of true Blood Alcohol Content would be between .075 and .085. The margin of error is higher on breath tests, but it's generally thought to be between one and two percent. We take the 2% benchmark if somebody blows into the breath test machine and the reading is .08 that would mean the true BAC is somewhere between .06 and .10

Do I have the right to an independent chemical test if I am arrested for DUI?

You do have the right to an independent chemical test if you're arrested for DUI. For example, if you elect to take the breath test, you have the right to have a subsequent blood test in order that a sample be preserved for later analysis, because a breath test does not preserve a sample of your breath. Also, if you elect to take the blood test, what will happen is a sample will be collected. A portion of that will be sent to the state crime lab for analysis, and a portion will be retained so that you can later have it re-examined by your own independent toxicologist.