A number of drivers in Palm Desert have heard about the blood-alcohol tests they might face if pulled over for suspicion of driving under the influence. However, many are unclear as to what these tests actually measure and how they are conducted.

Blood-alcohol tests measure a DUI suspect’s blood alcohol concentration, or BAC, by using a suspect’s breath, blood, hair follicle, saliva or urine. In most circumstances, law enforcement officials will use breath analysis to determine a suspect’s BAC level. However, if there is a serious accident or a suspect has refused a breath test, a blood screening may be conducted at the police station.

There are various machines that can be used to analyze a DUI suspect’s breath and determine BAC. The latest breath analysis machines, or breathalyzers, will use infrared spectroscopic analysis to measure the alcohol content of exhaled vapor. A computer will take the data collected and give a BAC measurement that shows the level of alcohol in the bloodstream. The legal limit in California is .08 percent. Studies have shown that popular methods used to fool a breathalyzer test, such as ingesting mints or onions, do not actually work.

However, blood-alcohol test results are not always accurate. Breathalyzer results in particular have been shown to be less accurate than blood tests. Breathalyzer machines need to be properly maintained and calibrated before use, and failing to do so could result in an inaccurate reading. The test must also be administered according to a particular set of guidelines. If the proper steps were not taken, breath test results might be successfully challenged in court. A successful challenge could mean dropped charges for those suspected of a DUI and avoidance of harsh penalties.