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Do Breathalyzers Discriminate Against Women?

Do Breathalyzers Discriminate Against Women?

Information courtesy of Lawrence Taylor - DUIblog

If you are arrested for DUI and a breath test shows a blood alcohol concentration (BAC) of .08% or higher, you are guilty. It does not matter, of course, whether you are a man or a women: the laws do not discriminate. Maybe they should...

Researchers at the University School of Medicine in Trieste, Italy, found that the stomach lining contains an enzyme called gastric alcohol dehydrogenase that breaks down alcohol, and that women have less than men. To determine the relative effects of the enzyme, they gave alcohol both orally and intravenously to groups of alcoholic and non-alcoholic men and women. They found that women reached the same levels of blood alcohol as men after drinking only half as much; with weight differences taken into account, they found that women reached BAC levels illegal in a DUI case after drinking 20 to 30 percent less alcohol than men.

The scientists conclusion: legislatures may need to consider sex differences in drunk driving laws when defining safe levels of drinking for driving motor vehicles. Frezza and Lieber, "High Blood Alcohol Levels in Women: The Role of Decreased Gastric Alcohol Dehydrogenase Activity and First-Pass Metabolism", 322(2) New England Journal of Medicine 95 (1990).

Yet another study has found that women have lower "partition ratios" of blood to breath. What kind of ratios? Well, all breath machines in DUI cases measure the amount of alcohol in a persons breath. But the what we really want to know is the amount of alcohol in the persons blood. So how do we get that? Simple: a small computer in the Breathalyzer multiplies the amount of alcohol it detects in the breath sample by 2100 times. This is based upon the theory that, on average, there are 2100 units of alcohol in the blood for every unit of alcohol in the breath. (Note: thats an average -- but it varies from person to person.) According to the study, women have a significantly lower partition ratio. Jones, "Determination of Liquid/Air Partition Coefficients for Dilute Solutions of Ethanol in Water, Whole Blood and Plasma", Analytical Toxicology 193 (July/August 1983). And the lower the ratio, the higher the reading -- even

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