Causes of Breathalyzer Error

Most states have some form of an implied consent law that comes into effect when a person is suspected of driving under the influence (DUI) of either drugs or alcohol. When an individual obtains a license from the Department of Motor Vehicles (DMV), they agree to submit to either a blood, breath or urine test at the request of an officer. A refusal can have serious consequences and the driver may have their license revoked for a period of time. A Breathalyzer machine is used to register the blood alcohol content (BAC) in a person's system. However, Breathalyzer errors can occur because the machines indirectly measure the amount of alcohol in a person's breath rather than the concentration in their blood.

How Breathalyzer Machines Work

Breathalyzer machines are manufactured under various brand names, including Intoxilyzer, Alco-Sensor, AlcoScan and BAC DataMaster. Each device uses a different method to estimate the alcohol concentration, and can end up producing widely diverse results. Some breath machines that use infrared technology detect any compound that contains the methyl or ethyl chemicals that are found in alcoholic beverages. Many handheld Breathalyzer machines use a silicon oxide sensor to determine BAC. These are prone to contamination and interference from other substances.

Why Breathalyzer Results Are Inaccurate

Breathalyzer errors can occur when machines that test a greater number of ethyl chemicals provide a false positive. This is due in part because of the cumulative effect when the machine adds all of the compounds together. The most common reasons Breathalyzer errors occur are:

  • Calibration—The internal settings of a Breathalyzer must be properly calibrated on a routine basis. Many handheld machines are required to be calibrated every six months. Higher end Breathalyzers require recalibration, but less frequently.
  • Hematocrit—Some machines assume that a person's hematocrit blood level to be at 47 percent. This does not take into account that hematocrit levels in men range from 42 to 52 percent and in women they range from 37 to 47 percent. An individual who has a lower hematocrit level will have a falsely higher estimated BAC.
  • Acid Reflux—Gastrointestinal reflux causes natural alcohols in the stomach to enter the person's mouth, mixing with their breath. People that suffer from this medical condition may burp up alcohol from their stomach. A false reading can occur even if the person only had one drink and belched right before the test.
  • Diabetics—People who suffer from diabetes might have high acetone levels. A byproduct of hypoglycemia is called ketoacidosis, which causes acetone to be produced in a person's breath.
  • Alcohol Absorption—The absorption of alcohol continues for a period of time after drinking. During this time, the distribution of alcohol in the body is not uniform. Some parts of the body will have a higher BAC than others.
  • Partition Ratio—Breathalyzer machines assume that the person being tested has a 2100 to 1 partition ratio. The amount of alcohol in 2,100 milliliters of breath is supposedly equivalent to the amount of alcohol in a milliliter of blood. The assumed partition ration converts the Breathalyzer reading to a predicted BAC level. But this ratio actually varies between 1300 and 3100 and causes inaccurate results.

People who regularly work with paint removers, gasoline or cleaning fluids may end up with a false positive result. Metered-dose inhalers used by asthma patients can also cause a Breathalyzer error.

Obtain Advice from a Defense Attorney

An experienced DUI attorney may be able to have the Breathalyzer results dismissed for several reasons. Police officers are only supposed to administer a breath test after carefully observing the suspect for a period of 20 minutes. They are required to watch for signs of burping or vomiting. Human error can also play a role when the BAC levels are misread or the test was improperly administered. Anyone who has been charged with a DUI should contact an attorney for legal advice and help with their specific case.