DUI/OWI Tests are Sometimes False By Mishlove and Stuckert, Attorneys at Law on January 31, 2023

If you are suspected of Operating While Intoxicated (OWI), you will be asked to submit to various tests to determine if you are impaired or if your Blood Alcohol Content (BAC) was over the limit.

However, a failed sobriety test, breath test, or even a blood test does not necessarily mean you were impaired or over the limit. All of these tests may give false results. No sobriety test is foolproof, and a skilled defense attorney will thoroughly investigate how these tests were administered to determine their validity.

Errors in Field Sobriety Testing

Several field sobriety tests are used in Wisconsin and all over the United States. These come from a federally promoted program called Standardized Field Sobriety Testing,or SFST. Each of these tests, however, can be inaccurate depending on how they are administered or interpreted. These tests include horizontal gaze nystagmus (HGN), walk-and-turn, and one-leg stand tests.

When administering the HGN test, law enforcement will hold up a finger or other object and observe your eye movement as they slowly move the thing across your field of vision. If the officer believes that you are not tracking the object consistently or your eye movements are unfocused or jerky, this may cause the officer to suspect intoxication.

Some underlying health conditions can cause the same kinds of eye movements at close range. In addition, if the test is conducted on a busy street, cars and pedestrians can cause eye-catching distractions that could lead to inaccurate results. At Mishlove and Stuckert, LLC, we have watched hundreds of squad car videos of police administering the HGN test. In most of these, we have seen severe errors in the administration of the test.

The nine-step walk-and-turn test and the one-leg stand test can also be impacted by the environment in which they are administered. The walk-and-turn test will require you to walk heel-to-toe for nine steps in a straight line and then turn. If you submit to a one-leg stand test, you will have to balance on one foot for a designated time while the officer looks for clues indicating intoxication. These clues are difficult, including using your arms to balance, putting your other foot down before the test is over, and hopping.

Many perfectly sober people cannot pass these tests. In Wisconsin, while they are allowed in evidence in court, these two tests may not be passed off as scientific.

Breathalyzer Tests Cannot Be Trusted

Law enforcement may also ask you to submit to a breathalyzer test at the arrest scene. Your defense attorney will carefully examine the machine's calibration during the test administration to ensure it was calibrated correctly and maintained. Certain medical conditions may also cause inaccurate breathalyzer test results. For example, low-carb diets, diabetes, hypoglycemia, or even a low fever could produce a false positive. The biggest issue in breath testing is called mouth alcohol contamination. Recent drinking or belching can cause a falsely high breath test result.

Inaccurate Blood Test Results Could Result in Dismissed Charges

Blood tests to determine BAC can be inaccurate depending on various factors. These factors include how the test was initially performed, as well as the transportation and storage of the sample. In addition, blood test administration is a strict process, and a small error at any stage could result in inaccurate results.

Andrew Mishlove is the developer and course director of the NCDD Serious Science, Blood Analysis, and Trial Advocacy courses offered to lawyers at the University of Texas-Arlington. This annual week-long course is the nation's leading course for lawyers on blood testing. Mishlove has trained hundreds of lawyers in blood alcohol testing and is always willing to share his knowledge.

The blood test process starts with the blood draw, where there are strict rules on how to cleanse the puncture site, what type of needle to use, how to find the vein after cleansing, what kind of vial to use, and how to handle the vial. The vials have an expiration date that is important for sterility. The vial must be adequately "inverted" to mix the sample with the precise proportions of preservatives and anticoagulants. If the mixture is off or the storage temperature is too hot or cold, the sample can ferment or even decompose. This process can lead to a false positive, depending on the sample's stage of decay.

We have seen laboratory errors from poor instrument maintenance, bad calibration, electrical errors, computer bugs, gas leaks, and human error in the laboratory. We have even seen samples mixed up!

The Bottom Line

There are two things your lawyer must do right away to defend you in any case: First, your lawyer must take the time to get to know you very well to understand your story. Second, your lawyer must have the knowledge and skill to investigate the case thoroughly, including the knowledge to obtain and interpret police videos of the field-testing and breath testing processes, as well as all laboratory records –not just the one-page test result, but the hundreds of pages required in any lab test.

Investigating these errors will often be your lawyer's first course of action when building your defense.


Related to This

Andrew Mishlove and Lauren Stuckert

Mishlove and Stuckert, LLC Attorneys at Law

Mishlove & Stuckert, LLC Attorneys at Law has been rated the #1 OWI/DUI law firm in the state by Wisconsin Law Journal Reader Rankings. Our OWI/DUI specialists have been highly rated by organizations including: 

  • Avvo™
  • Super Lawyers
  • Martindale-Hubbell 
  • Better Business Bureau 

To speak with one of our board-certified OWI/DUI defense specialists, request a consultation online or call us at (414) 332-3499.

Contact Us

"Mr. Mishlove was worth every penny and then some. I would consider him the Michelangelo of the DUI defense world.
He is professional, dedicated, and pours his heart into his job. I would give him 10 stars if I could."
Ronald S.

Rate, Review & Explore

Social Accounts Sprite