PAS Test vs. Chemical Breath Test

PAS Test vs. Chemical Breath Test

DUI attorney breathalyzer traning

Usually when I talk about a Breathalyzer test, it’s referring to either the roadside Preliminary Alcohol Screening (PAS) test or the chemical test that is administered at the police station. However, these are two completely different tests with different requirements and potentially different legal ramifications.

The PAS test is part of the roadside sobriety tool kit that officers carry around with them. As a field sobriety test kit, it can be easily used and gives a general idea of the blood alcohol content (BAC) of the person taking it. However, because it is not a fully accurate test (with results varying up to 15% from actual BAC), the court does not recognize the test for legal reasons. The truth is that one out of every four people tested will show a higher BAC than they actually have.

There are all kind of environmental factors that can influence the results of a PAS breathalyzer test, including:

  • Police radios
  • Dirt
  • Smoke
  • Cleaning products
  • Breath mints
  • Cell phones
  • Nail polish
  • Gasoline
  • Relative humidity

It is important to note that the PAS test, as with all field sobriety testing, is completely optional. Refusing to take the PAS will, however, result in your license being taken and a trip down to the local precinct for a mandatory chemical breath test.

Chemical testing can be broken down into the stationary breath analysis, a blood test, or a urine test. The stationary breath analysis works on the same principles as the field PAS test. The major difference is that the test is administered in the controlled environment of a police station. Many of the potential contaminants are removed in this test. Still, blood or vomit in the mouth or even irregular breathing patterns can influence the results of a Breathalyzer test.

The most accurate of all tests is the blood test. It is either taken at a hospital or at the police station. These are the least convenient and most expensive of all BAC tests and are usually only done at the request of an officer who feels the Breathalyzer is not accurate. Even these tests have potential for misrepresentation or even inaccuracy if they are not administered correctly. People who have diabetes or who have been taking cough medicine or herbal supplements can show higher than normal BAC levels. Also, if an alcohol swab is used to clean the area before a blood draw, the alcohol may be picked up on the sample.

A more common alternative to the blood test is the urine test. The biggest drawback to these tests is that they take much longer to process, so some jurisdictions would rather not use them. The test can be administered at the police station, at a clinic or hospital, or even at the subject’s own home. Tests must be verified off-site by an authorized lab.

The most important thing that you should know is that a PAS test is voluntary and the officer administering it is required by law to tell you so. If you are not advised of this, it is considered an illegal search. But if you do refuse the PAS, you could be setting yourself up for a longer license suspension, jail time, or even the installation of an ignition lock device if you are ultimately convicted.

By Ted Burgess

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