James G. Wigmore, Forensic Toxicologist, Speaker, Author

Breath alcohol testing has numerous advantages over blood alcohol testing and are so apparent that more and more countries have switched alcohol testing of suspected drinking drivers from blood to breath. Globally there are several million breath tests conducted a year, not just for drinking drivers but for workplace safety as well. The case for breath alcohol testing is strong.

The Case for Breath Alcohol Testing
  • Breath alcohol testing is noninvasive and safe. No hypodermic needles are required to collect breath and, hence, there is no possibility of injury or transmission of disease.

  • Breath results are known immediately compared to the several days or weeks required for blood results to be analyzed and reported by forensic laboratories. Therefore, police can determine on the spot what charges to lay and whether medical treatment for the drinking driver is required (such as alcohol poisoning).

  • There is no chain of custody and/or storage or transportation problems. The breath sample is provided directly into the breath alcohol instrument. No special blood tubes, swabs, identity seals, biohazard refrigeration or special transportation are required as is for blood samples.

  • No medical staff are required for breath analysis. This is important for large countries such as Canada where the medical staff may be many hours of travel away. The breath tests may be conducted at the police station or in mobile vans allowing the time between the arrest and alcohol analysis to be reduced significantly.

  • In countries with mandatory blood sampling, there is the problem of real or alleged “blood or needle phobia” in the drinking driver.

Disadvantages of Breath Alcohol Testing

The 2 main disadvantages of breath alcohol testing compared to blood is that conscious co-operation of the subject is required for the breath test and currently no other drug analysis can be conducted on breath.

Refusal Rates in America

These advantages are being undermined, however, by high breath alcohol testing refusal rates in numerous jurisdictions. The National Highway Traffic Safety Administration determined that the average breath test refusal rate in the US ranged between 19 to 25 percent between 1987 and 2011. The US states with the highest breath test refusal rates are shown in the following Table:

The 3 jurisdictions with the lowest breath test refusal rates were Puerto Rico (1.3%), California (4%) and Maine (4.9%).

The study concluded that:

Breath alcohol concentration (BAC) test refusals by suspected impaired drivers are a challenge for impaired driving enforcement and prosecution.


Namuswe, E.S., Coleman, H.L, and Beming, A., “Breath Test Refusal Rates in the United States- 2011 Update”, NTSA Report # DOT HS 811, 6pp, March 2014

WOA Update

I’m hoping that if you follow my blog, you’ve also taken the step to become a member of the WOA Community. If you haven’t, please consider doing so as I just issued another update to my book Wigmore on Alcohol: Courtroom Toxicology for the Medicolegal Professional. You can join by providing your name and email address in the box to the right. Its free and I don’t spam my members with frivolous content.

Upcoming Forensic Events

Keeping up to date and staying connected to the forensic community should be a focus of all of us in the field. Gratefully, October provides us with lots of ways to connect. Below are some workshops and conferences that I’m aware of:

Saturday October 11th, 2014. The California DUI Lawyers Association present a seminar on “Blood is Thicker than Breath” at the Orange County Airport Hilton Hotel organized by Josh Dale. I am presenting a lecture on “Forensic Breath Alcohol Testing. A View from the Great White North”. Register here: http://rgn.bz/mf1B

Monday October 20th 2014. I will be presenting a 3 day workshop on “Aspects of Forensic Alcohol Toxicology: Not Just Drinking and Driving” at the Southwestern Association of Forensic Scientists Annual Conference on South Padre Island, Texas. The workshop is organized by Alex Madrigal II. Register here: http://rgn.bz/MFFC