There are some states in America where a sobriety test includes walking a straight line while touching your nose, but at Integrity Sampling (and for the majority of police forces around the world) a more scientific approach is used, and this starts with the breathalyser.
First and foremost, let’s clear up a common misconception. A breathalyser doesn’t measure blood alcohol concentration or BAC. Blood analysis is required to measure BAC, which is why a breathalyser is only the first step in testing (more on this later in the article).
What a breathalyser does do is estimate the amount of alcohol on a person’s breath. Alcohol shows up in the breath of a person who has consumed an alcoholic drink because alcohol travels from the mouth, through the throat, to the stomach and other organs, including the lungs, and into the bloodstream. Therefore, the amount of alcohol that is exhaled from your lungs provides an excellent indication of the amount of alcohol in your blood.
An excellent indication, but it wouldn’t stand up in a court of law. That’s because breathalyser accuracy can be ‘tricked’ by a variety of factors including body temperature, ambient temperatures and electrical interference. The quality of the breathalyser also comes into play. Breathalysers used by Integrity Sampling and the Police are state of the art and regularly calibrated; those in pubs and available for purchase for little more than $100 aren’t.
So why are people charged with driving over the limit after a positive preliminary breathalyser test? Put simply, they aren’t. A positive preliminary breathalyser test is an indicator. Further, more conclusive testing is required. This conclusive testing can involve having a blood test, a urine test, a saliva test or undergoing breath testing using an approved breath analysing instrument.
People in workplaces who are tested by Integrity Sampling using a breathalyser are afforded the same rights as those on the road. Breathalyser results are only preliminary and further testing is carried out before any determination is made.