For people who are stopped on a suspicion of drunk driving, one of the tests that is sometimes used to determine if they are intoxicated is the breath test. Last week, we discussed how proper calibration of a breath test machine is vital; however, improper calibration isn't the only thing that can affect a breath test result. A variety of other factors can also affect the result of the breath test. Our Maryland readers might like to know more about this.
There are some basic factors, such as the hematocrit level, that people can't control that play a part in the blood-alcohol content percentage that is given by the breath test. Because of the limitations of a breath test machine, the assumption is made that all humans have an identical hematocrit level. That isn't the case, men have an average hematocrit level of 47, while women have an average level of 42.
If a person has a hematocrit level that is above the male-female average of 45, the BAC reading will be higher than the actual concentration level. That means that a man who has a hematocrit level of 52 who gets a reading of .10 on the breath test would actually have a BAC of .08.
Other factors that can affect BAC readings on breath tests include body temperature, stress, certain medications, snuff or chewing tobacco use and some medical conditions. Heartburn and diabetes are two medical conditions that can lead to false high readings.
The fact of the matter is that breath tests aren't all that accurate. They are meant to be a preliminary test, but not all jurisdictions view them that way. Those who have been stopped and given a breath test prior to an arrest should learn about their rights to fight the charges placed against them.
Source: Alcohol Problems and Solutions, "Prevent Unjust Conviction for DWI or DUI Charges" David J. Hanson, Ph.D., accessed Feb. 19, 2015