Help Me Hank: Do at-home or pocket breathalyzers actually work?

It’s unfortunate, but it happens every day in Michigan. 

Last year, almost 32,000 people were arrested for driving under the influence and 251 people were killed in accidents where a drunk driver was behind the wheel. 

We don’t want those numbers to get higher as we head into the time of year when drinking and driving tends to increase with the highest arrests happening near the holidays. 

So we want to know…could a home or pocket breathalyzer be the secret to keeping you safe?
Do they really give you a blood alcohol content (BAC) that’s accurate in a quick and safe way?

We’re putting three to the test. 

1.    Digital Breath Alcohol Tester - $20
2.    BAC Track Detector keychain - $30
3.    BAC Track keychain with a Smartphone App - $50

In order to do this safely, our coworker agreed to test these out against a preliminary breath test (PBT) administered by Michigan State Police Lieutenant Mike Shaw. (And yes, we had a plan to safely get our coworker home before we even stepped foot in the bar!) 

After about 4 drinks and 30 minutes, we were ready to test these out and here are the results. 


  • Professional PBT reading: .08
  • Digital Breath Alcohol Tester reading: .14
  • BAC Track Detector keychain reading: .13
  • BAC Track keychain with a Smartphone App reading: .10


While all the home testers had higher results than his actual BAC level registered with the PBT, it still shows up wrong and quite inaccurate. We also found that the tester with smartphone app, took a couple tries at first to score any reading at all. 

Lieutenant Mike Shaw brought up a good point, these results happen to be higher, but it could easily go the other way. “You don’t know where it came from, where it’s been made, where it’s been, you don’t know any of that stuff that goes into the product. You have to use common sense” he says. Even if you drop your keys a couple times, you could be messing with how the device calibrates your BAC. 

Help Me Hank tests the tests (WDIV)

Did you know, there’s more that goes into testing your BAC level as well? You could start testing your levels before it settles into your blood stream, which will affect you. Lt. Shaw says police do other preliminary testing, waiting 20 minutes after your last drink or even burp to make sure the test is legitimate. That way there’s no alcohol left in your mouth. 

Ultimately, Lt. Mike Shaw says even with the official acronyms on the devices, they’re still not reliable saying, “that’s garbage. If you decide, hey I want to try a piece of junk to maybe test where I am supposedly, you should take an Uber.”

The big takeaway from this test…if you think you should test your BAC level before you get behind the wheel, you shouldn’t be driving at all. It’s important to have a ride home decided before you step into the bar. Lt. Shaw says once you walk in…it’s too late to be making decisions. 


About the Authors:

Hank Winchester is Local 4’s Consumer Investigative Reporter and the head of WDIV’s “Help Me Hank” Consumer Unit. Hank works to solve consumer complaints, reveal important recalls and track down thieves who have ripped off people in our community.