When it comes to smartphone-enabled breathalyzers, buyer beware.
All AlcoMate handheld breathalyzers are DOT/NHTSA approved, which specifically means that they have passed a battery of performance tests. Not only do devices undergo 20 rounds of precision and accuracy trials, tests are also conducted to ensure proper operation against temperature ranges, vibration and false positives.
The DOT (Dept. of Transportation) and NHTSA (National Highway Traffic Safety Administration) does not even accept for consideration any breathalyzer that is smartphone-enabled; effectively, the only government approval system for breathalyzers does not consider this to be a legitimate feature, but just a gimmick. The problem then, is this: since smartphone-enabled breathalyzers are not accepted for accuracy testing, they are released to market without any third party verification of their performance or accuracy, and the only statements related to performance are just marketing claims.
Make sure to do your research when selecting a breathalyzer, and be certain that the device you select is DOT approved for accuracy.