A breathalyzer is a portable device used by law enforcement to estimate a person’s blood alcohol concentration (BAC) by analyzing a breath sample. While generally reliable, these devices can sometimes produce inaccurate readings due to various factors, including certain medications.
How Breathalyzers Detect Alcohol
Breathalyzers primarily rely on two scientific principles to detect alcohol: fuel cell technology or infrared spectroscopy. Fuel cell breathalyzers contain platinum electrodes that cause an electrochemical reaction when alcohol is present in the breath. This reaction oxidizes the ethanol, producing an electrical current directly proportional to the amount of alcohol in the breath sample.
Infrared spectroscopy breathalyzers, often larger and used in police stations, identify alcohol molecules by how they absorb infrared light. These devices emit infrared radiation, and the reduction in light intensity after passing through a breath sample indicates the alcohol concentration. Both technologies are specifically calibrated to detect ethanol. These devices then estimate blood alcohol content based on a breath-to-blood partition ratio, typically around 2100:1 or 2300:1.
Medications That Can Affect Readings
Certain medications can lead to inaccurate breathalyzer results, either by containing alcohol or by being metabolized into compounds that mimic it. Over-the-counter cold and cough remedies, such as Nyquil or certain Vicks products, often contain ethanol, which can temporarily elevate breath alcohol readings. Similarly, oral gels used for pain relief, like Anbesol, may contain significant alcohol concentrations. Mouthwashes and breath sprays also frequently contain alcohol, and their recent use can result in a false positive as residual alcohol lingers in the mouth.
Asthma inhalers, including those with albuterol, budesonide, or salmeterol, can contain compounds with molecular structures similar to ethanol. These substances can remain in the airways and trigger a false positive on a breathalyzer test.
Individuals with diabetes may also face false positives due to diabetic ketoacidosis (DKA), a condition where the body produces ketones, including acetone, when it burns fat for energy. Some breathalyzers, particularly older models, can misinterpret acetone as ethanol. Acetone can also be further metabolized into isopropanol, another alcohol that could be detected.
A rare medical condition known as auto-brewery syndrome involves the body’s digestive system fermenting ingested carbohydrates into intoxicating quantities of ethanol. This internal alcohol production can be linked to an imbalanced gut microbiome, sometimes following prolonged antibiotic use. Individuals with this syndrome can exhibit symptoms of intoxication and register high blood alcohol levels without consuming alcoholic beverages.