Why the Breathalyzer Often Gives False Readings

Imagine you’ve just been pulled over. You have no reason to be nervous—you may have been going over the speed limit, but you haven’t been drinking. But the officer decides to give you a breathalyzer test, and the results come back positive. How is this possible? A number of ways, it turns out: it’s long been recognized that breathalyzers are sensitive to and can be affected by a number of factors, including temperature, calibration, and interfering compounds. Often, the outside temperature affects the results of the test, especially if the instrument isn’t properly calibrated. And since the instruments are sensitive, they need to be adjusted often, which doesn’t always happen.

Sometimes, even when the instrument is properly calibrated, the machine will identify compounds similar in chemical makeup and structure to alcohol as being alcohol, thus leading to an artificial blood alcohol level (also known as BAC). Though newer models are better at distinguishing chemicals, the instrument used to test you may be an older model. Probably the most common reason of artificially high BAC readings, though, is the presence of mouth alcohol: the machine measures the alcohol content in the mouth, and not the stomach. Often it gives accurate readings from the air from your lungs, but it is often mistaken, and a small amount of mouth alcohol can have a large impact on the BAC reading.

But most of those factors have to do with the breathalyzer itself. Before we even get that far, there are in fact reasons having more to do with you. Elevated body temperatures are one of the most common—if your body temperature is higher than 98.6 degrees because of sickness, this will lend itself to a higher BAC. Additionally, many over the counter medicines contain alcohol and can also thus contribute to a higher BAC. Lifestyle and dietary choices also play a role in measuring BAC. Specifically, gastro esophageal reflux disease (GERD) has been known to lead to higher BAC readings when stomach liquids are released back into the mouth because of the reflux. And things you may have taken recently—such as Altoids, gum, or tobacco—have also been known to lead to artificially high readings. Diabetics are generally known to have higher acetone levels than the general population; acetone is a chemical similar to alcohol that breathalyzers often mistake for alcohol. Additionally, during the actual test, breathing patterns can the readings: it has been found that holding one’s breath, or being out of breath after, say, exercising, will lead to significantly higher BAC readings.

Many of these factors are fairly common, and it isn’t out of the ordinary that they interfere with the breathalyzer test, so it’s important to keep in mind the type of things that can affect BAC readings and be aware of them.

Breathalyzer Houston – DWI Defense

Operating a motor vehicle with a BAC of.08% or higher may result in an Austin driving while intoxicated (DWI) arrest. The officer may administer a breathalyzer test to determine a driver’s BAC. This test calculates the amount of alcohol in the bloodstream by analyzing the amount of alcohol in the driver’s breath.

While a breathalyzer test is a scientific method for determining blood alcohol content, it is not without flaws. Many DWI defense attorneys have received training on these breathalyzer machines and can identify flaws in the test administration or the machine itself. As a result, there is still hope if you were arrested after failing a breathalyzer test. There are numerous Austin breathalyzer defenses that can be used to help your DWI case.

Breath Testing May be Inaccurate

Breath tests have the potential to produce inaccurate results. Most breathalyzer machines assume a 2100:1 blood-to-breath ratio in a person’s body; however, this ratio does not apply to everyone. If a person’s ratio is lower than the standard ratio used on a breathalyzer, the results of his or her breath test will be inflated.

During the breath test, the temperature of the breath sample must be 34 degrees Celsius. Even if the sample temperature is 1 degree above this, the reading may be inflated by up to 7%.

A breath test can be influenced by certain medical conditions. Intestinal issues, hiatal hernias, or gastric reflux may cause test errors. Dental work can also trap alcohol in the mouth, causing the results to be exaggerated.

Before administering the blood test, officers must observe the driver for at least 15 minutes to ensure he or she does not vomit. Both vomiting and belching may have an impact on test results.

A high protein diet, for example, could result in a higher BAC reading. When a person consumes a high protein diet, he or she enters ketosis, which causes ketones to be converted into isopropyl alcohol.

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