• The new wristband that measures blood alcohol content through your skin. (BACtrack)Source: BACtrack
Breathalyser manufacturers have developed a new product that could make responsible drinking fashionable, by measuring blood alcohol levels via sweat.
Shami Sivasubramanian

23 May 2016 - 11:18 AM  UPDATED 23 May 2016 - 12:45 PM

San Francisco based tech manufacturer and industry leader in breathalysers, BACtrack, have just developed a new state-of-the-art blood alcohol measuring tool in the shape of a wearable wristband similar in style to a Fitbit.

It's called Skyn, and BACtrack claim the wristband detects BAC (blood alcohol level) through sweat. It could be used by both law enforcement and individuals for self-monitoring.

“We are thrilled to win the Wearable Alcohol Biosensor Challenge. We’re excited to bring BACtrack Skyn to market to aid researchers and treatment providers in collecting more reliable data and ultimately, make advances in healthcare treatment.” - Keith Nothacker, Founder & CEO of BACtrack.

More specifically, the wristband detects BAC using "transdermal monitoring (via an electrochemical sensor) to track the ethanol molecules escaping through your skin" which are then analysed via an app on your smartphone. 

"While most consumed alcohol is processed within the body, some escapes through the skin in the form of ethanol. As a result, we're able to read this ethanol signal, and use our proprietary algorithm and device calibration to convert the raw response reading to an estimated Blood Alcohol Content (BAC) reading," reads their website.

BACtrack also shared the video below to explain the product further.

Ultimately, the wristband's fame comes after recently winning the grand prize at the US National Institutes of Health's Wearable Alcohol Biosensor Challenge. The challenge encouraged research into non-evasive and discreet blood alcohol measuring tools.

BACtrack was awarded US$200,000 (about AUD$280,000) towards the product's further development, as part of their prize.

The wristband mitigates a number of problems faced by breathalysers, including the fact that some mouth washes can skew BAC readings. Since alcohol is not absorbed through the skin, Skyn is free of this pitfall. But that does not mean the new wristband is completely foolproof either.

Professor Kourosh Kalantar-Zadeh from the School of Engineering at RMIT is sceptical about the new wristband's ability to accurate measure a person's BAC using sweat.

"Alcohol is first absorbed through the blood stream and then released through sweat which is made up of several other properties. It isn't a direct measure like a blood test. So it’d be interesting to see how accurate a measure this really is.

“How much a person sweats depends on their physiology. So if someone sweats more or have been more physically active while wearing the wristband, they may release the sweat in larger quantities, sweat with a higher metallic content, which might lead to inaccurate readings," he tells SBS Science.

After taking a drink, it can take around 45 minutes for ethanol to be released from pores; a breathalyser provides a more immediate result.  However once detected via the skin, a person's BAC can be monitored on a second-by-second basis.

Prof Kalantar-Zadeh also queries the longevity of the product, claiming most electrochemical skin sensors he has dealt with over his career have a short shelf life due to the caustic nature of common elements used in these sensors which erode as they react with sweat.

Prof Kourosh Kalantar-Zadeh from RMIT says given current state of technology sweat could erode the sensor in wristband over time. (BACtrack)

"Can you use the wristband more than once? For one month or two months?" he asks.

Though BACtrack have yet to publish a detailed paper on how their product works, Prof Kalantar-Zadeh believes that for the Skyn wristband to be successful, BACtrack must have developed a “rather impressive” protective barrier on the sensor to prevent erosion from sweat.

But regardless of the new device and its aging competitor, the breathalyser, Prof Kalantar-Zadeh believes the only accurate measure of BAC is a blood test.

Reuters reports that BACtrack has yet to submit Skyn to regulatory boards for approval, but expects to make them available for purchase by the end of this year. 

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