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How accurate is a Breathalyzer test?

On Behalf of | Jul 26, 2021 | Drunk Driving Defense

If you’re driving home and get stopped on suspicion of drunk driving, an officer may ask you to take a portable Breathalyzer test. You have the right to refuse to give a sample on this portable device without risking your driver’s license. However, you don’t have the same leeway when it comes to the Intoxilyzer breath test at the police station.

Breathalyzers are usually fairly accurate, but only when they are calibrated correctly and when the test is given in the right manner. For example, did you know that using mouthwash before the test could cause a false positive? Also, that acetone released in your breath due to diabetes or from following a keto diet could trigger a false positive? Even indigestion could lead to a high blood alcohol concentration (BAC) result despite not drinking much at all. These false results could lead to a DWI charge.

Breathalyzers may misread some kinds of alcohol

These devices that analyze your BAC detect the ethanol on your breath. Unfortunately, other kinds of alcohol can also be in your system and trigger false positive results. In the aforementioned case of a diabetic dealing with hyperglycemia, their bodies release acetone as a side effect of ketoacidosis. This is a dangerous sign of a medical emergency, but they may just register as being drunk.

Intoxilyzers need good calibration

To know if the calibration is off, you should be able to compare two test results taken within a quarter hour of one another. Both should be within .02% of each other. If they are not, then the Intoxilyzer’s results should be questioned to make sure that they are accurate.

The accuracy of these tests may make a difference in your case. Defending yourself against inaccurate tests is essential.