False Readings and Alcohol Detection with Breathalysers

False Readings and Alcohol Detection with Breathalysers

A recent article released by Andatech discusses the accuracy of breathalysers, false readings and how best to prevent them. To understand all of this in more detail it’s important to know the how the body absorbs and processes alcohol and how breathalysers process this information to give you a reading. 

Alcohol in Your Body

According to Andatech within minutes of consuming alcohol it is absorbed into the bloodstream via the stomach and small intestine. Once in the blood stream it travels around the body and spreads though out organs via the presence of water content.  91% of the alcohol is eventually broken down via the liver, with the remaining amount leaving the body via urine, breath and sweat. With this in mind, three quarters of a standard alcoholic drink takes at least an hour to leave the body. However, sobering of the person may take longer and cannot be accelerated by coffee, vomiting, fresh air or exercise to name a few of the myths.

Breathalysers: What You Need to Know

While alcohol is still present in the blood system, breathalysers are able to give a reading on the person’s blood alcohol content (BAC) level. There are two different types of breathalysers, both utilising different technology. The first type is the semiconductor breathalysers which are used mainly for personal and home use. These use a tin-oxide material which is less accurate making these types cheaper. The second type uses platinum fuel cell technology to accurately give a reading. These types are usually more expensive and used for professional or work use as they have an increased accuracy. With the increase in fuel cell technology, these types are becoming more affordable and being used more for personal use. Both use mouth pieces to provide a reading but readings can vary depending on the type of breathalyser used.

What Are False Readings

False readings are errors which can occur in the reading given. An example could be a positive reading to alcohol in the bloodstream after no alcoholic beverages have been consumed. As semiconductor devices use cheaper material in their sensors they are prone to give false readings if over used and that is why they are most suitable for personal and home use to give reliable readings.

Some of the ways false readings can occur are by;

Low calorie diets: Low calorie diets produce more ketone due to the increased fat cell break down. Ketone has a similar chemical structure as alcohol and is more present in the user breath due to this.

Mouth alcohol: This can be present after consuming anything with alcohol present, such as mouth wash. Alcohol evaporates quickly when used in these situations because at body temperature it is highly volatile.

Diabetics: Acetone can be produced in the air within the lungs when blood sugar is high and cannot be metabolized due to diabetes. Acetone once again has a similar chemical structure to alcohol which can cause false readings from breathalysers.

Others chemicals: If alcohol based hand sanitizer has not been properly rubbed in and given time to dry it may cause a false positive reading. As well as alcohol based substances, cigarette smoke, hair spray, paint fumes, varnish and plastic adhesives can also cause false readings in breathalysers. 

Avoiding Breathalyser False Readings

The best way to avoid any chance of false readings is to use breathalysers with fuel cell sensors. These sensors are more sensitive and less likely to give positive readings when they encounter ketone, acetone, cigarette smoke, mouth wash and so forth. With this said they are still sensitive to methyl alcohol, isopropanol, carbon monoxide and diethyl ether.  A waiting period of 15-20mins should be given before testing if the person has been exposed to these agents.

For increased reliability there are several steps which can be followed; mouthpieces should be changed for every user, waiting 15mins before each test after consuming food, drink and cigarettes and making sure the breathalysers have been calibrated per manufacturers recommendations.

As you can see a lot of factors come into play to cause false readings. So it’s important to make sure you purchase a reliable breathalyser and keep it calibrated according to the manufactures recommendations to ensure your readings are as accurate as possible.