How Are Blood Alcohol Tests Taken?

Wisconsin residents who are accused of drunk driving may be subjected to blood alcohol tests. These tests, often involving the taking of a blood sample, are a way for law enforcement to gather evidence against a driver who has been alleged to be driving while drunk. Oftentimes, the results of these tests are entered into evidence during criminal trials, thereby putting an individual at risk of being convicted and being subjected to serious penalties.

So how are blood tests taken for alcohol testing purposes? First, an elastic band is wrapped around the test subject's arm in order to stop blood flow and enlarge the veins below the band. Then, the person drawing the blood sample will use a non-alcohol solution to clean a needle and use it to draw blood from one of the enlarged veins. Once the blood is collected, it may then be tested.

Can any missteps here affect the outcome of a blood alcohol test? Absolutely. For example, if a needle used to collect a blood sample use sterilized with an alcohol-based solution, then the blood-alcohol content may read higher than it actually is. Also, taking cough medicine or certain herbal supplements may skew the test's readings, giving the impression that one's blood-alcohol content is higher. There also may be errors during the actual testing of the blood.

Therefore, simply because blood alcohol content tests show that an individual is over the legal limit for driving does not mean that the test subject actually was intoxicated under the law. However, without appropriately challenging a blood test result's validity, a court may deem them valid. So those who have been accused of drunk driving need to ensure that they know how to defend themselves and draw the prosecution's claims into question, lest they be subjected to penalties that they may not deserve.

Source: WebMD, "Blood Alcohol," accessed on Oct. 2, 2016