What is the Difference Between a Breathalyzer and Blood BAC Test?

When pulled over for a DUI, the officer on the scene will want to measure your blood alcohol concentration, or BAC, in order to gather evidence sufficient to convict you of the crime. They may do so if they have reason to believe you have been driving while impaired, either by giving you a field sobriety test or noting signs that you are impaired, like red eyes or evidence of alcohol in your car. If asked to take a breathalyzer test prior to arrest, you are allowed to politely decline taking the test. In most cases, the officer will already have gathered enough probable cause to arrest you for a DUI anyways, at which point you will have to submit to either a breathalyzer or blood test to measure your BAC. Refusing to submit to one of these chemical tests will result in an automatic license suspension of one year, under California's administrative per se law. Under this law, the California DMV will suspend the driving privileges of anyone who refuses to submit to a BAC test when arrested for a DUI. The arresting officer should notify you of the blood test alterative to the breathalyzer test at the point of arrest. You might wonder what test you should opt to take. There could be a difference in the BAC reading between the two and you don't want the wrong choice to convict you if you are on the edge of the legal limit. There are a few differences between these two tests. The first most obvious of differences is the method of the test. For a breathalyzer, you simply blow a breath sample into a hand-held machine. A blood test is done with a blood draw. You will have to provide a blood sample and many people do not enjoy this process. Many find the blood test much more invasive than the breathalyzer test. Another difference is the overall precision and accuracy of the tests. The breathalyzer test measures the amount of alcohol in your breath, not your blood. The chemistry of how it measures that alcohol is complex and sophisticated but involves measuring the oxidation of the alcohol in your breath. However, under Henry's Law, the alcohol in your breath can be indicative of the alcohol in your blood because the alcohol dissolved in your blood is proportionate to the alcohol in your breath. Today, breathalyzers are very accurate if they are maintained, calibrated and used according to procedure. However, at best, they are an estimate of your BAC and things like mouth wash are known to provide false positives. For some, you may not want to risk your criminal record for an indirect measurement. The blood test directly measures the alcohol concentration or content in your blood. In this respect, it can be more accurate than the breathalyzer, in so much that it rarely can provide false positives and there is no machine to be maintained or calibrated. However, the blood test BAC reading can be inaccurate for other reasons. The drawing and testing of blood samples is a science. It involves trained professionals and scientific measurements but still can result in errors. The most accurate BAC reading that will indicate your BAC at the time you were driving should be taken as soon as possible after the arrest. This isn't always the case and can be problematic. After you stop drinking, your BAC will decrease with time. However, if you were drinking immediately prior to being arrested, your BAC may keep rising after you are arrested if it hasn't already fully entered your blood stream. This is because alcohol usually does not enter your blood stream the instant you swallow it. Alcohol will enter your blood stream, and thus will be detectable in a blood test, at varying rates, depending on what you drank, the contents of your stomach and your overall health and composition. If when you are driving you still have alcohol in your stomach but later, at the station, that alcohol has left your stomach and entered your blood stream, your blood test may not reflect your BAC at the time you were driving. Keep this in mind when you think about your defense. If too much time had passed since you were pulled over before the blood test was taken, the BAC reading may not be accurate. Contact an experienced DUI defense attorney right away if you feel this may have been the case with your arrest. There are also chemicals called ketones that can raise your BAC from a blood test. Ketones can be in your blood as a result of a medical condition so speak to an attorney if you feel that you may have a condition that results in high ketone levels in your blood. It is important you question your BAC if you feel it was not accurate. The science of BAC testing is never exact and can be filled with variables and flaws. Don't let yourself be convicted of a DUI based on inaccurate readings.

Have you or a loved one recently been arrested for a DUI? Contact attorney Christopher Martens and his legal team. Experienced in DUI and drug charge defense, our Visalia area legal team can ensure you take the right steps towards challenging your BAC reading and fighting your charges. Call our Visalia or Hanford, CA offices at 559-967-7386 or email us at MartensLaw@gmail.com for a free consultation.