How accurate are breathalyzers?

 Posted on May 24, 2024 in DUI Charges

The breathalyzer can seem like a foolproof tool for measuring blood alcohol content (BAC). But how accurate can it really be?

Breathalyzers work by measuring the amount of alcohol in your breath. They convert the data collected to an estimated BAC using a specific ratio. In theory, it’s a clean process. However, things get interesting when considering factors that can influence accuracy.

Routine calibration

Like any instrument, breathalyzers need regular calibration to ensure consistent results. Maryland has strict protocols for the calibration procedure, but any lapse in maintenance can lead to faulty readings. An attorney can challenge the test’s validity if calibration records are missing or incomplete.

Maryland uses two types of breathalyzers. The first is Preliminary Breath Tests (PBTs) for roadside screening, which are hand-held breathalyzer units used by police officers on individuals suspected of by asking them to DUI to blow into it while on the side of the road. PBTs are less accurate than the stationary machines used at police stations and are not admissible as evidence in court.

On the other hand, an evidentiary breathalyzer test offers a more precise BAC reading. These devices are not as handy, require more controlled and regulated conditions, and are usually situated at police stations, detention centers or testing facilities. The results are entirely admissible if the breathalyzer test is conducted at a station or barrack.

Biological factors

Individual factors can throw off perfectly calibrated machines. Metabolism, body weight and recent consumption of certain foods can affect the breath-to-blood alcohol ratio. This means the breathalyzer reading might only partially reflect your actual BAC.

Breathalyzers are a valuable tool for law enforcement but are not infallible. Blood and urine tests are generally more precise than breath tests but require a more formal process.

Understanding the potential for inaccuracies can empower you. If you’re pulled over and suspect a breathalyzer issue, you may politely request a blood test instead. You may also consider consulting a legal professional if you face DUI charges. Remember, knowledge is power, especially when protecting your rights.