Smartphone breath alcohol testing devices vary widely in accuracy

Penn Medicine research finds that some devices failed to detect drivers were over the legal driving limit more than half the time.

With several studies demonstrating that drinkers cannot accurately estimate their own blood alcohol concentration (BAC), handheld alcohol breath testing devices, also known as breathalyzers, allow people to measure their own breath alcohol concentration (BrAC) to determine if they are below the legal limit of .08% before attempting to drive.

Person at bar waving away a drink offered while holding car keys with smartphone laying on bar next to them.

The latest generation of personal alcohol breath testing devices pair with smartphones. While some of these devices were found to be relatively accurate, others may mislead users into thinking that they are fit to drive, according to a new study from the Perelman School of Medicine.

The findings, published in Alcoholism: Clinical & Experimental Research, compares the accuracy of six such devices with that of two validated alcohol-consumption tests—BAC taken from venipuncture, and a police-grade handheld breath testing device.

“All alcohol-impaired driving crashes are preventable tragedies,” says lead investigator M. Kit Delgado, an assistant professor of emergency medicine and epidemiology at Penn. “It is common knowledge that you should not drive if intoxicated, but people often don’t have or plan alternative travel arrangements and have difficulty judging their fitness to drive after drinking. Some may use smartphone breathalyzers to see if they are over the legal driving limit. If these devices lead people to incorrectly believe their blood alcohol content is low enough to drive safely, they endanger not only themselves, but everyone else on the road or in the car.”

This story is by Kelsey Odorczyk. Read more at Penn Medicine News.