A wearable breathalyzer called the BACTrack Skyn nabbed the top prize at the National Institutes of Health (NIH) Wearable Biosensor Challenge this week, Reuters reports. The wristband uses fuel cell technology to measure a person's Transdermal Alcohol Content, or blood alcohol levels through the skin.

Because the device measures ethanol through a person's skin instead of in their blood, it cannot provide real-time information. It takes around 45 minutes for alcohol to be transmitted through the skin. The BACTrack Skyn, which is still just a prototype for now, connects to an app via Bluetooth.

Interesting, but not that useful

The startup behind the wearable, simply called BACTrack, says the device is not meant to be a replacement for the kind of breathalyzers police officers use, but rather something that can provide a "recent history" of alcohol use. "It can help doctors accurately measure a patient’s drinking history, and not just depend on the most recent tests," George Koob, head of the NIH's National Institute on Alcohol Abuse and Alcoholism, told Reuters. "This can help a lot with the treatment."

Many of the wearable breathalyzer prototypes entered into the competition worked similarly to the BACTrack. One exception was a temporary tattoo that changed colors depending on the amount of alcohol detected through a person's skin, according to the NIH.

The BACTrack isn't available to the public yet, and hasn't been submitted to the FDA for marketing approval, Reuters reports. BACTrack says "limited quantities" of the wearable will be available for preorder this fall.