A breathalyzer is a device used to estimate a person’s blood alcohol content using a breath sample. Although the word “Breathalyzer” is actually a brand name trademarked by the breath analyzer’s inventor, the term has since become a commonly used term to refer to all breath analyzation tests used in the field. Today, breathalyzer tests are commonly used by law enforcement officers during traffic stops when the driver is suspected of driving under the influence of alcohol. The results of breathalyzer tests are not infallible, but in general, the courts accept such evidence of a motorist’s impairment. To explore this concept, consider the following breathalyzer definition.

Definition of Breathalyzer


  1. A device used to measure a person’s blood alcohol content using a sample of his breath.
  2. A brand name breath analyzer.


1954    Trademark registered by device developer Robert Frank Borkenstein

What is a Breathalyzer

While many people are aware of the instrument, some may be asking themselves, what is a breathalyzer? A breathalyzer is a tool used by law enforcement to determine whether a driver is under the influence while operating a motor vehicle. Breathalyzers are breath analysis testing instruments into which a suspect must blow a stream of air. The device estimates the individual’s blood alcohol content (“BAC”) as grams of alcohol per mL of blood. While the indirect means of testing BAC does not produce perfect results, its results have been proven to be quite accurate and reliable.

History of the Breathalyzer

Though the Breathalyzer was not trademarked until 1954, inventive minds were working on the idea of a non-invasive test for determining an individual’s level of drunkenness as early as 1874, when Francis E. Anstie learned that tiny amounts of alcohol were produced in a person’s breath. In 1927, Emil Bogen wrote a paper on the possibilities of testing for alcohol residue in a person’s breath, after conducting a study in which individuals inflated football bladders by mouth to provide a sample for the test.

That same year, a chemist named William Duncan McNally invented a device that detected chemicals in the breath. McNally’s device had breath moving through chemicals suspended in water, causing the water to change color. The device was intended for use by housewives to test the drunkenness of their husbands after a night out with the boys.

The first breath analyzer that could practically be used at the roadside, called a “drunkometer,” was developed in 1931 by Rolla Neil Harger of the Indiana University School of Medicine. This device captured an individual’s breath in a balloon inside the machine. The breath sample was then passed through a solution of acidified potassium permanganate, which changed color if there was alcohol in the breath sample.

In 1954, Robert Frank Borkenstein, an Indiana State Police captain and professor invented the first known breathalyzer. This device used chemical oxidation to determine the alcohol content of a person’s blood. The device was patented on May 13, 1954. In 1967, Tom Parry Jones developed the first electronic breathalyzer instrument.

Breathalyzer Test

A breathalyzer test is often given after a suspect is made to perform a field sobriety test. It works by having the suspect exhale into the device, which measures the amount of ethanol present in the breath. An electric current is produced and measured by a microprocessor, then displays the results. Breathalyzer tests, and their acceptance as evidence in court, are regulated by each state, though there are certain general requirements concerning their use. In order for the results of a breath analyzation test to be admissible in a court, these requirements must be met:

  • The breathalyzer device must be on a list of acceptable devices as specified by state guidelines
  • The breathalyzer device must be properly maintained and checked for accuracy periodically
  • The individual administering the test must be certified to use that breathalyzer model
  • The suspect must not have eaten, smoked, vomited, or drank hot or cold liquids immediately before the test is administered
  • The test must take at least two measurable readings that produce results within .02 percent of one other to show the breathalyzer accuracy

Breathalyzer Accuracy

The breathalyzer is the most commonly used test to determine a person’s blood alcohol content when it comes to DUI/DWI cases. A breathalyzer test is not as accurate as a blood test, but the results are typically regarded as accurate if the test is administered properly. However, there is some controversy among scientific and medical professionals concerning breathalyzer accuracy as some experts have come forward to debate the issue.

In 1985, Dr. Michael Hiastala, Professor of Physiology and Biophysics at the University of Washington, expressed his opinion that breath testing is not an accurate method of measuring blood alcohol content (“BAC”), as there are too many variables at work. One study has shown that breath alcohol test readings may vary 15 percent from the subjects’ actual blood alcohol levels. Regardless of the controversy concerning breathalyzer accuracy, tests are still used in the United States to determine whether an individual is driving under the influence.

Refusing to Take a Breathalyzer Test

In all states, driving is a privilege, not a right. Because of this, the courts can revoke a person’s license for refusing to take a breathalyzer test when it is suspected he is endangering others by driving under the influence of alcohol. In the U.S., “implied consent laws” state that, by taking advantage of the privilege of driving, the driver has automatically given consent to have his blood alcohol content tested. This means that the individual has given up his right to refuse such a test, and if he does, he surrenders his driving privileges.

Most states suspend the license of a driver for refusing to take a breathalyzer test or blood alcohol test for up to 12 months. Any driver with a prior DUI conviction may have his license suspended even longer for refusing to take a breathalyzer test. In some states, refusal to submit to a BAC test can result in fines and/or jail time.

It should be noted that results from a breathalyzer test are not absolutely required for prosecution. The state’s prosecutor may charge an individual with DUI, and proceed with prosecution based on other evidence, such as the observations of the law enforcement officers, results of field sobriety tests, and testimony of witnesses.

For example:

Tammy is driving home after drinking beer all afternoon with her friends. When police stop her, Tammy fails a field sobriety test, being unable to engage in the simple tests of coordination and reasoning. The officer asks Tammy to take a breathalyzer test, but Tammy adamantly refuses. In Tammy’s state, there is no warrant process for obtaining breathalyzer tests. Tammy is arrested and later charged with driving under the influence.

At trial, although no blood alcohol content data is available, the prosecutor provides testimony of the police officers who stopped Tammy for driving erratically, and who administered and witnessed the field sobriety test. In addition, the prosecutor introduces testimony from two employees of the bar where Tammy and her friends were drinking, as well as another person who witnessed Tammy’s drunken driving. In this case, the breathalyzer test results are not strictly necessary, as there is plenty of evidence to convict Tammy of DUI.

Warrant for Breathalyzer Test

Because many intoxicated drivers, in an attempt to avoid self-incrimination, refuse to take a breathalyzer test, some states have adopted a process of issuing warrants for law enforcement to perform the test, taking away the suspect’s right to refuse. Modern technology makes it possible for law enforcement officers to obtain warrants electronically on their mobile devices, eliminating the possibility that the suspect will sober-up before an actually paper warrant could be obtained. Once a warrant has been issued for a blood alcohol test, refusal to provide a sample is subject to an additional criminal charge for contempt of court, and usually results in the forced drawing of a blood test.

Portable Breathalyzer

The invention of the portable breathalyzer has made it possible for people to test their own breath alcohol content (“BrAC”) to determine whether they can legally drive. The market has become saturated with portable breathalyzers designed for at-home use. Portable breathalyzers come in all shapes, sizes, and prices. Some are more accurate than others, and boast a higher price tag. A few tester models are even compact enough to fit on a keychain, and can be used with a smartphone app.

From a legal perspective, law enforcement and legal professionals recommend not relying solely on the results of a portable breathalyzer test, as driving while intoxicated at any level is dangerous.

How to Beat a Breathalyzer Test

It is never a good idea to drink and drive. Most people are aware of this, but many try to “sober up” before sliding behind the wheel. There are many myths suggesting how to beat a breathalyzer test, many of which are bizarre to say the least. Although countless websites, books, and blogs claim to offer the answer to how to beat a breathalyzer test, the only true way to sober up, and reduce the BAC level, is to let enough time pass so the alcohol can leave the bloodstream. Drinking strong coffee, slamming an energy drink, or chewing gum has no effect on BAC.

Some of the myths focus on “tricking” the breathalyzer test, rather than actually reducing BAC. These methods, such as sucking on a penny, or eating a handful of breath mints however, and are reliable solutions for people asking themselves how to beat a breathalyzer test. This is because the breath used to measure BAC comes from deep in the lungs, not from the mouth, and have nothing to do with the odor of a person’s breath, but actual alcohol in the breath. Passing that air through a minty-fresh mouth simply doesn’t work.

Legal Blood Alcohol Content Levels

The DUI laws of each state vary, though all have agreed on the maximum blood alcohol level considered to be legal. Even if a person does not feel the effects of the alcohol he has been drinking, his blood alcohol content may be over the state’s legal limit. The legal BAC level is under .08 percent, though a commercial driver may be prosecuted for DUI at a level of .04 percent or higher. A driver under the legal drinking age of 21 years may be charged with DUI for even a minute BAC. Punishment for driving with a BAC over the legal limit varies by state, as well as by the specific circumstances, whether anyone was injured or property damaged, and whether the individual has prior DUI convictions.

Breathalyzer Tests Suspended Pending Investigation

In April of 2015, prosecutors in several Massachusetts counties, including Middlesex and Essex counties, suspended the use of breathalyzers by law enforcement officers. The suspension of use was the result of concerns being raised about whether the tests were being administered properly, whether the machines had been properly calibrated, and the lack of reliability in these circumstances. With the possibility of people being convicted due to faulty tests, the Executive Office of Public Safety was called in to investigate.

The Executive Office of Public Safety issued a report in Many 2015, stating that about 150 of the 40,000 test results reviewed should have been deemed invalid. The report also discussed the requirement for police officers to calibrate their breathalyzer devices to operate in a specified range. After the report, the Executive Office of Public Safety began working closely with various District Attorneys to identify defendants who were convicted for DUI/DWI due to a breathalyzer test operator error. Many defense attorneys also began looking back into old cases to determine whether their clients had been wrongfully convicted.

Related Legal Terms and Issues

  • Consent – To approve, permit, or agree.
  • DefendantA party against whom a lawsuit has been filed in civil court, or who has been accused of, or charged with, a crime or offense.
  • Intoxicated – A state in which an individual’s normal ability to act or make reasonable decisions is inhibited by drugs or alcohol.
  • JurisdictionThe legal authority to hear legal cases and make judgments; the geographical region of authority to enforce justice.

Leave a Reply

Your email address will not be published. Required fields are marked *