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Alcohol Testing 101

alcohol testing

Alcohol Testing: History, Methods, and Problems

Alcohol testing methods have developed steadily over the last few decades. It’s almost hard to believe that just 80 years ago, testing for blood alcohol content (commonly known as BAC) relied solely on blood and urine tests, which were expensive and time consuming.

History of BAC Testing
Doctors have known since antiquity that analyzing a patient’s breath can reveal much about their health and sobriety. With the advent and advancement of toxicology, scientists have been able to identify and measure different substances in the blood with increasing accuracy.

However, it was not until 1927 that chemists began experimenting with breath tests for alcohol.1 In 1938, Dr. Rolla Harger developed the first road-side BAC breath test, which was jokingly named the “Drunkometer.”2 Other scientists followed suit, and began aiding local police departments across the country.

In 1954, Professor Robert Borkenstein invented and patented the first “Breathalyzer. While the Drunkometer needed to be recalibrated every time it was moved, the Breathalyzer was more stable and easily portable.3 However, critics of Borkenstein believe his credentials are highly overstated.4

Scientists continued to develop more effective and reliable methods for BAC breath testing, while more studies concluded that driving under the influence was a considerable risk to personal and public safety.

Alcohol Testing Today
There are three methods of BAC testing in use today: breath, blood, and urine testing.

Breath testing is the most common and popular method, as it is easy for law enforcement to administer on-site. The suspected drunk driver blows into a small device, which measures the concentration of evaporated alcohol molecules in their breath.

Blood testing and urine testing are used less often, as they are more difficult to administer, and more invasive. Blood testing requires a blood sample to be drawn from the suspect with a needle, whereas urine testing would require the suspect to urinate into a sample cup on the side of the road.

Many practical difficulties arise with these testing methods, unless the suspect can be taken to a hospital or police station where the tests can be administered safely and privately. This, in turn, can also alter the results of the BAC test, due to the time elapsed between being pulled over and taking the sample.

However, while road-side breathalyzer tests are the easiest and most practical, they are not always as accurate as you may think. Because they measure alcohol residue from the mouth, esophagus, and lungs, they estimate BAC indirectly. Furthermore, factors like metabolism, vomiting, body temperature, mouth wash, and even breath mints can affect the breathalyzer test and produce an inaccurate result.

What Should I Do If Pulled Over?
If you are pulled over under suspicion of DUI, keep the following in mind:

  • A blood test is the most accurate measure of your BAC. If you know for certain that you are under the limit, opt for a blood test.
  • Blood tests can show the presence of other substances – including prescription drugs – in your system, which could inadvertently expose criminal liability, or show an adverse reaction to a medication.
  • Breathalyzers and urine tests are less accurate, and are thus less reliable as evidence in court. If you have been made to take a breathalyzer or urine test, found over the limit, but wish to fight your case in court, consult your lawyer and find a forensic toxicology expert witness to review your BAC test results.


1 “History of the Breath Test,” http://www.liquorlaws.net/breathtest.html

2 Matt Novak, “Drunk Driving and the Pre-History of Breathalyzers,” December 31, 2013, http://paleofuture.gizmodo.com/drunk-driving-and-the-pre-history-of-breathalyzers-1474504117

3 “History of Breathalyzers,” http://breathalyzer.org/history.html

4 T. Venjnovic v Kamala Harris 2014 Case No.: 2:13-CV-02474-JAM-EFB Document 10-1: I.a.14 (Cal. Supreme Ct.)

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