How a DUI Breath Test or Breathalyzer Can Malfunction

August 4, 2021 Don Pumphrey, Jr. Criminal Defense, Drunk Driving/DUI Social Share

When stopped by a police officer under suspicion of driving under the influence, you or a loved one may have to take a breathalyzer, breath test, or sobriety test. It also might be called an “Intoxilyzer”, but this name just refers to a more dated version of a breathalyzer test. To learn more about Intoxilyzer tests specifically, visit our blog post here, and to learn more about DUI breath tests on the Intoxilyzer, visit our blog post here. A breathalyzer is more objective than a sobriety test during which officers direct the drivers to perform certain tasks that measure the driver’s impairment level, so most officers will use the breathalyzer test in order to get more “accurate” results. However, not all breathalyzer results are accurate, and these tests can be subject to many kinds of malfunctions that will skew results and render them unreliable.

How Does a Breathalyzer or Breath Test Work?

The Breathalyzer is the most famous portable device that tests a driver’s breath for alcohol content. These devices measure the amount of alcohol in the driver’s exhaled breath to calculate the amount of alcohol in the driver’s blood, giving a blood alcohol concentration (BAC). Here is how it works:

• The driver ingests alcohol, which enters the stomach and small intestine, and then is absorbed into the blood.
• After just minutes of drinking alcohol, the driver’s BAC can be measured and usually reaches its peak sixty minutes after consuming the drink.
• About ninety percent of alcohol consumed by the driver is filtered through the liver, and the rest is eliminated from the body through urine and breath.
• The breathalyzer converts the amount of alcohol in the exhaled breath into a BAC.

What is the Legal BAC Limit?

In the United States, a driver’s BAC cannot be over 0.08 percent. For underage drivers, there is a “zero tolerance” policy wherein the younger driver cannot have any detectible alcohol level. When the National Highway Traffic Safety Administration sponsored studies on drunk driving or driving under the influence, they found that essentially all skills needed for safe and reliable driving are substantially impaired at the 0.08 BAC level, which is why that number is the legal limit.

When Can a Breathalyzer or Breath Test Malfunction?

Breathalyzers, like any other device or machine, are prone to malfunction and error. For this reason, they are not as accurate or reliable as blood tests that can be used to determine impairment levels in drivers. In fact, peer-reviewed and uncontested studies show a margin of error of fifty percent when comparing breathalyzer estimates of BAC to blood alcohol content. Therefore, a breathalyzer reading of 0.1 percent could represent a BAC between 0.05 and 0.15 percent, forming an unreliable basis for determining guilt in a DUI case. Here are some instances or factors that could render an inaccurate or unreliable breathalyzer result:

• Foreign substances, like:
  • Smoking
  • Breath mints
  • Alcohol-based mouthwash
  • Dental medication

These substances can present in the mouth and contain alcohol which will lead to a false positive since the amount of alcohol vapor emitted will be greater than the amount exhaled in the breath.

• Medical conditions or behaviors, like:
  • Diabetes
  • Body temperature
  • Alcoholism
  • Fasting or dieting
  • Ketosis
  • GERD (to learn more about this condition specifically, visit our blog post here)

Many of these conditions or body behaviors can give inaccurate breathalyzer results because many of these conditions can raise the numbers of BAC due to the concentrated vapors that do not represent actual impairment.

• Calibration

Breathalyzers have to be calibrated periodically and maintained with fresh batteries in order to maintain and ensure accurate readings. Generally, breathalyzers should be calibrated every six months.

• Software

Breathalyzers use special software for BAC detection similar to computers and their operating systems, and these technological marvels are prone to bugs and glitches just like any other kind of software or program.

• Human Error

Just like any other machine, the breathalyzer is prone to human error. The failure to operate the breathalyzer properly, like having the suspect take multiple tests and waiting the Floridian 20-minute rule before testing, could all result in inaccurate results.

• Environmental factors, like:
  • Paint fumes
  • Chemical emissions

Environmental factors, like paint fumes, chemical emissions, varnish, plastics, and adhesives can trigger false results. These false results can occur because breathalyzers can confuse the molecular structure of these environmental factors with other similar molecular structures.

Tallahassee DUI Defense Lawyer

If you or a loved one are pulled over by an officer and subject to a breathalyzer or Intoxilyzer test, it is imperative to retain a DUI defense attorney as soon as possible to discuss your options and possible defenses. Don Pumphrey, a Tallahassee DUI defense lawyer, and the Pumphrey Law firm have years of experience defending clients against DUI charges and will ensure each defense is explored in the favor of you or a loved one’s case. Contact Pumphrey Law Firm today at (850) 681-7777 or send an online message for an open and free consultation with a defense attorney on our team.

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