Do Breath Test Machines Discriminate Against Females?

We’ve already blogged about how breath test machines sometimes give false positives in the case of low carb diets but recent research might show that the breath test machines might in certain situations be biased against women in general.

Alcohol and Gender Research

A human’s stomach lining contains gastric alcohol dehydrogenase, an enzyme that breaks down alcohol. Studies at the University School of Medicine in Trieste, Italy, show that women have less of this lining compared to men.

To further determine the effects of this discovery, researchers gave alcohol to groups of non-alcoholic and alcoholic men and women both intravenously and orally. Results of these tests showed that women only had to drink half as much alcohol to reach the same blood alcohol levels as the men. After taking weight differences into account, it was found that women reached illegal BAC levels after drinking 20 to 30 percent less alcohol than the men.

Women and Partition Rations

In all DWI cases, breath machines measure the amount of alcohol in an individual’s breath. But since what officials really want to know is the amount of alcohol in the individual’s blood, the Breathalyzer (DataMaster DMT in Minnesota) simply multiplies the amount of alcohol detected in the breath sample by 2100 times. This computation is based on the theory that there is an average of 2100 alcohol units in the blood for every unit of alcohol in one’s breath.

However, another study shows that women have considerably lower partition ratios of blood to breath. The lower an individual’s partition ratio, the higher the reading on the breath test machine. This means that a woman accused of drunk driving may be deemed guilty, while a man with the same blood alcohol level may be considered innocent.

Birth Control

Studies in Canada show that women who take O.C.S. or oral contraceptive steroids appear to eliminate ethanol considerably quicker than women who do not take O.C.S. What does this research mean? That women can not only reach peak BAC faster, but can also return to lower levels more quickly than men. This can cause problems in a DWI case that estimates an individual’s BAC at the time of driving when the breath test is administered an hour later.

Researchers have also discovered that women who are either pregnant or ingesting birth control pills prove to have higher levels of acetaldehyde on their breath. This is due to their reduced capability to metabolize enzymes as their levels of sex steroids increase.

The majority of all breath machines utilize infrared analysis to measure a DWI suspect’s breath sample. However, these machines do not measure alcohol. Instead, the machines really measure a compound that contains the methyl group in its molecular structure. Since acetaldehyde is one of these compounds, a breath best machine could erroneously show a higher “blood alcohol” reading.

Conclusion

What conclusion is to be made from all these various studies from all over the world? That legislature may want to take sex differences into consideration and reassess drunk-driving laws that define safe drinking levels for drivers that operate motor vehicles.