Is a South Carolina breath test really accurate?

Breath tests are often used to determine whether people in South Carolina have been drinking but evidence suggests they may not be accurate.

The South Carolina Department of Public Safety reports that almost 27,000 arrests were made in the state last year for drinking and driving. When people are stopped for a traffic violation, officers may ask them to take a breath test to determine whether they have been drinking. However, is the breath test really accurate?

It's not science

Most people think that a breath test is a scientific tool that law enforcement use to measure alcohol in a person's blood. However, the National Motorists Association states that this is far from the truth. Science is based on established formulas that always produce an accurate reading such as a blood test.

However, studies that have compared the readings of breathalyzers against the results of a blood test show over and over again that the breathalyzers are often inaccurate. One such study showed that the measurement from a breathalyzer is subject to a 50 percent margin of error. This means that a person's actual blood alcohol content level may be over the reading or under it. This can lead to innocent people being charged with a DUI.

Alcohol isn't the only substance measured

The Sociology Department at the State University of New York points out that one problem with many breathalyzers is that they don't only detect ethyl alcohol - the chemical compound found in alcoholic drinks. There are many other compounds that are similar in structure to the molecules in ethyl alcohol and some machines will detect these compounds and use them to compute the person's blood alcohol level.

One compound a machine may detect is acetone. Acetone levels are higher in people who are dieting or have been diagnosed as diabetic. As such, if people with these kinds of health issues are tested, their BAC could indicate that they are impaired, when in fact, they have not consumed one drop of alcohol.

Factors that affect breath test results

In addition to health conditions and the error margin, there are many other factors that have been shown to affect a BAC reading on a breath test. These include the following:

  • Tobacco smoke
  • Police radios and cellphones
  • Dirt
  • Blood
  • Temperature of the person and environment
  • Physical activity

Exposure to chemical-laced products can also raise a person's BAC level. In one experiment, a person painted a wall with a gallon of oil-base paint after taking a piece of plywood and putting content cement on it. While the person had not consumed any alcoholic beverage, a breath test showed a .12 BAC level, well over the legal limit of 0.08.

When people in Greenville are charged with driving under the influence, they should understand that they have rights and options. Therefore, it may be of benefit for them to sit down with an experienced criminal defense attorney.