Reliability of the Breathalyzer Test

Breathalyzer tests estimate blood-alcohol levels.

In an effort to reduce the problem of drunk driving, most law enforcement agencies today use breathalyzers to estimate blood-alcohol content (BAC). The reliability of breathalyzer tests continues to be debated.

Models

Hand-held devices present the most varied and questionable results, leading some courts to outlaw the use of their results. Larger models provide extremely accurate results and are used as evidence in court.

Body Chemistry

Breathalyzers read all chemicals with the methyl compound structure as alcohol. Human breath naturally contains many chemicals with similar structures. Diabetes and dieting can also cause false positive readings.

Environmental Agents

Many environmental substances, including paint, paint thinners, gasoline and some cleaners, cause false high BAC readings. Blood, vomit, tobacco smoke, electrical interference and variations in the surrounding temperature or that of the subject can also skew readings.

Assumptions

Breathalyzers estimate the actual BAC level of individuals by making assumptions about various body functions, including hemocrit and breath alcohol levels. These levels vary among people.

Usefulness

Breathalyzers sometimes give inaccurate results, but their proper use proves beneficial to society at large. Law enforcement officers use hand-held devices to determine probable cause and then require an individual to submit to very accurate testing with a larger unit, which tests alveolar air from deep in the lungs. Breathalyzer training and re-certification courses ensure proper use and reduce questionable readings.

References

• Potsdam: Driving While Intoxicated Information
• Potsdam: Facts and Information
• Potsdam: Breath Analyzer Accuracy
• Virginia Tech: Estimating BAC
• New Jersey Division of Criminal Justice: Mandatory In-Service Law Enforcement Training

Resources

• Potsdam: Tongue Studs and Breathalyzer Tests