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Breathalyzers: how do they work?

The breathalyzer is a breath alcohol-testing device invented in 1954 to assist police in assessing blood alcohol concentration (BAC) levels. Breathalyzer devices do not measure exact levels of blood alcohol concentration. Rather, the devices make estimates based on measurements of alcohol in the breath.

When a person drinks alcoholic beverages, the alcohol is absorbed into the blood stream through the mouth, stomach and intestines. The blood then moves through the lungs where some of the alcohol enters the air sacks and is exhaled, providing an indicator of how much alcohol is in the blood stream.

If a law enforcement officer suspects someone of drunk driving, the officer may take a breath test reading to detect alcohol. To measure the alcohol, the officer will ask the driver to breathe into the device.

The air exhaled will bubble through a chemical mixture in the breathalyzer device. If the chemical mixture changes color, there is alcohol present. The greater the color change, the higher the blood alcohol concentration.

Are Breathalyzer Results Accurate?

Breathalyzers are generally accepted as accurate indicators of BAC, even though they only estimate BAC rather than test it directly like DUI blood tests. Among other problems, the breathalyzers used by police officers can be sensitive to temperatures and improperly calibrated. They can also be affected by compounds in a person’s breath.

If there is reason to believe that the breathalyzer is inaccurate, a defendant may be able to challenge the results of the breathalyzer in court.

Currently, the Minnesota Supreme Court is reviewing a lower court’s decision that source code problems with the Intoxilyzer 5000EN did not affect the breath test machine’s accuracy. This particular DUI breath test uses infrared technology to measure how many particles of alcohol are in the breath sample and then converts it to a BAC reading. The test’s source codes end up determining whether or not a person should be charged with DUI. If the case is successful, hundreds — even thousands — of defendants may have cases dismissed.

Breathalyzer Results Used as Evidence

In most states, driving with a .08 BAC or higher is a criminal offense. If an officer discovers that a person is driving under the influence (DUI) or driving while ability impaired (DWAI), the officer will take the person into custody and file drunk driving charges. During the court hearing, the breathalyzer result will likely be used as evidence against the driver.

In Colorado, even a first DUI offense can result in severe consequences such as fines, jail time and driver’s license suspension. If a driver is arrested for drunk driving, it is very important to consult with a Colorado drunk driving defense attorney right away. The attorney can work to have the charge dismissed or to minimize the consequences of the charge.