While our breathalyzers are easy to use, mistakes can happen if one does not follow the manual correctly.
Generally, before taking a test you should wait at least 15 minutes after drinking alcohol. Eating a meal with alcoholic ingredients or smoking a cigarette also has impact on the measured value!
Without this delay, the residual alcohol inside your mouth will make the value higher than it should be. The given number will hence not reflect your actual BAC (Blood Alcohol Concentration).
To ensure accurate results, remember to give the device at least one minute for recovery before taking another test. This will also expand the lifespan of your device.
Not calibrating your breathalyzer at least once a year will also lead to inaccurate results.

Blowing into the mouthpiece too shortly or with a too low breath volume will result in a failed test (usually the devices will recognize this).
Try to breathe into the device with medium strength, as if you were whistling. After around one second, the breathalyzer will detect the airflow and start beeping. Do not stop blowing into the mouthpiece at this point. Bear in mind that the device finishes the test, not the user!
Measuring your BAC should take around four seconds. After that timespan, you should hear and feel a clicking noise caused by the internal pump telling you that the test is finished.

Additionally, the measured value is dependent on a number of various factors, including:

Psychical and physical condition

Tiredness will make the alcohol enter your blood slightly faster. Additionally, people in a weakened condition will feel the impact of alcohol stronger. How your body deals with alcohol is strongly tied to various individual preconditions. The body fat percentage, weight and gender of a person also play an important role: For example, women can usually stand less alcohol since they have less muscular tissue and more adipose tissue.[1]

your physical condition has impact on your BAC

Stomach contents

eating large meals makes your body break down alcohol faster

Drinking with an empty stomach will make the alcohol go into your blood much faster. After eating a large meal, you will take longer to reach your maximal BAC.[1] Drinking non-alcoholic beverages (e.g. water) during the alcohol consumption will help your body reducing your BAC much faster.[2]

Manner of drinking alcohol

People who rarely drink alcohol will need longer to break it down. Drinking a high amount of alcoholic beverages within a small time will cause your BAC to rise much faster and also results in a higher per mille value.[2]

drinking faster will give you a higher BAC

You can check out more factors that have impact on your alcohol breakdown in our blog article about common alcohol myths. 😉

[1] Student Well-Being McDonald Center, University of Notre Dame: “[Alcohol] Absorption Rate Factors
[2] National Health Service: “Alcohol Myth Buster