If a Breathalyzer is properly calibrated and maintained, the test is properly administered, and the person who is taking the Breathalyzer does not have a medical condition that would prevent an accurate test, a Breathalyzer test can be accurate. However, there are a variety of factors that play into a reliable test and if any of these components are not present, the Breathalyzer test will not be accurate.
BAC is a reliable and consistent indicator of driver impairment only under a very limited set of circumstances. Blood alcohol content can be tested well after a person has been driving. Thus, it is not necessarily a reliable indicator of a person’s blood alcohol content at the time that they were driving.
The validity of testing for blood alcohol content is dependent upon a variety of factors. If any one of those factors is not handled properly, for example, the way the sample is collected, stored, or analyzed, then the results of the testing may not be a reliable indicator of impairment.