Tag Archives: breath testing

Ohio DUI Law: The Hematocrit Defense

English: Two drops of blood are shown with a b...

How bloody is your blood?  The hematocrit is the number expressing the cell volume of blood (the size and number of red blood cells in proportion to the rest of the blood).  As humans, we all have a natural variation in our hematocrit.  Healthy men have a natural variance from 40.7% to 50% and healthy women have a natural variance from 36.1% to 44.3%.  The hematocrit level is a moving target.  Illness, hydration and stress can cause variations in the [Read the full post. . .]

DUI Science and More Faulty Breath Machine Assumptions

Evidential Breath Testing Measures The Amount of Alcohol In Your Breath Not in Your Brain!

A chimpanzee brain at the Science Museum London

One of the faulty assumptions underlying evidential breath testing is the assumption that the tests are measuring the ability of alcohol to impair your brain.  They do not.  The breath test does not care how, or even if, the alcohol is impairing your brain only that it is in your breath via your lungs via your blood.  The machines do not test venous blood but [Read the full post. . .]

Residual Mouth Alcohol, Slope Detectors and the 20 Minute Observation

Someone using a breathalyzer

One of the most prevalent causes of error in breath-alcohol analysis is the presence of alcohol in the mouth.  This residual mouth alcohol (hereinafter R.M.A.) contaminates the expired breath captured by the machine and elevates the test results radically.  The BAC Datamaster’s computer is programmed to assume that a breath test reading is 100% deep-lung (alveolar) air.  This captured “deep-lung” air is then multiplied by 2100 pursuant to the accepted and scientifically defensible partition ratio.[1] Using these built-in [Read the full post. . .]

Dayton DUI Law: The GERD Defense


Regurgitation and Reflux are not the same thing!  Reflux is the movement of ethanol vapor back up the esophagus from the stomach which has the ability to contaminate a breath sample.  The defendant who suffers from Gastroesophageal Reflux Disease (GERD) will not exhibit outward signs of distress or other signs which a breath testing technician would likely notice.  The surging ethanol vapor can cause an elevated reading on an evidential breath testing device.  The elevated test can appear following a [Read the full post. . .]

I Did Not Refuse!

ACT Police Breath Testing/Command truck

If you were tested on an Intoxilyzer 5000 breath test machine, the source-code (software inside the machine) may have been rigged against you.  One of the most dramatic happenings in the science of a DUI has been the developments of the source-code battle taking place in Minnesota.  Ohio has recently rejected the Ohio-made BAC DataMaster in favor of the Intoxilyzer breath test machine (often referred to as the Intoxi-LIAR) so we can soon expect similar science-based battles in the [Read the full post. . .]