Blood Alcohol Content & DUI Testing

What is Blood Alcohol Content?

Blood Alcohol Content is commonly referred to as BAC. A person’s BAC is the percentage of alcohol that is in their bloodstream at any one time. It is determined by dividing grams of alcohol by 100 milliliters of blood. For example, a BAC of .10 percent means that an individual’s blood supply contains one part alcohol, for every 1,000 parts blood.


A person’s blood alcohol content is what is tested by police during a suspected drunk driving traffic stop, to determine whether or not a driver has had too much to drink. In Michigan, the legal limit for alcohol consumption is .08, which means that if your BAC is .08 or higher, you are presumed to be drunk. That will likely cause you to be arrested for drunk driving and have to face criminal charges. Some drunk driving offenses in Michigan and other offenses result in felony charges. Either way, it’s not good.


How is BAC tested in Michigan?

When an officer pulls someone over for suspected drunk driving, whether it’s in Grand Rapids, Lansing, Jackson, St Johns, in the Detroit area, or anywhere else in Michigan, they are likely to ask that person to perform a series of tests to determine their level of intoxication. These tests often include what is known as “field sobriety tests” or “roadside sobriety tests”. This will include asking the person to perform a series of actions that are more difficult for intoxicated people, like walking in a straight line, touching the tip of their nose with their fingertip, and reciting the alphabet with their eyes closed. You have an absolute right to refuse to do these field sobriety tests. Refusing them is neither a criminal offense or a civil infraction here in Michigan.


In addition to the roadside sobriety tests, officers usually require that a person submit to a Preliminary Breath Test (PBT). This test is given roadside on a handheld unit that police officers carry in their patrol cars. The test requires that the suspect blow into a straw that is connected to the PBT equipment. If done correctly, the PBT equipment gives a digital readout of the the BAC. If not done correctly, the blow might be considered a technical refusal to take the PBT test.


Do I have to take the preliminary breath test?

Refusal to take the roadside PBT in Michigan is simply a civil infraction. You will not be charged criminally for refusing a PBT and no points will be levied against your driver’s license.


Do I have to take the post arrest chemical test?

Understand that a “post arrest chemical test” means a test, after you have been formally arrested. Chemical testing can mean the use of a DataMaster machine at the police station or jail. It can also mean a blood draw or urinalysis. Police are required to first advise you of your implied consent rights. If you refuse the post arrest DataMaster / blood draw / urinalysis after hearing your implied consent rights, your driver’s license will be suspended. A first offense refusal is for one year. However, it is not a crime to refuse this test.This is because when you receive your driver’s license from the state, you are in effect, consenting to submit to a chemical test after your arrest.


Can medications or illness affect my BAC results?

While BAC readings are often relatively accurate in Michigan, there are a number of things that can cause inaccurate results. This can mean that you would then be falsely accused of operating under the influence of alcohol when in fact you were not over the legal limit of intoxication at the time of your arrest.


Certain medications like those used to treat diabetes, asthma and ulcers can alter your chemical test results. Be careful because various,over-the-counter medicines like Nyquil and Pertussin also include alcohol and can affect your BAC readings. Recent use of mouthwash can also confuse the readings, along with having recently vomited. Other factors that could affect your BAC test results are having dental bridges or caps, and having open wounds or sores in your mouth.


How does my BAC affect me?

It isn’t possible to determine how each person will react to alcohol, as each person’s body is different and many factors can affect the way in which alcohol is metabolized inside the body. Some of those factors include age, weight, gender, tolerance, and food consumed before drinking. Remember that any BAC that is .08 or more, presumes that you are over the legal limit to be driving a vehicle.


However, allowing for the fact that each person will react differently to alcohol, there are certain symptoms of alcohol consumption that are generally applicable to a majority of people. According to information provided by, the following side effects are common at each level of consumption:



– Feeling of Relaxation

– Sense of Well-Being

– Thought, Judgment and Coordination are Impaired



– Loss of Inhibitions

– Extroversion

– Reflexes, Depth Perception, Peripheral Vision and Reasoning are   Impaired



– Emotional Swings

– Sense of Sadness or Anger

– Reaction Time and Speech are Impaired



– Stupor

– Blackouts

– Motor Skills are Impaired



– Severe Depression

– Unconsciousness

– Breathing and Heart Rate are Impaired



– Breathing and Heart Rate are Impaired

– Death is Possible


Drunk Driving Attorneys

Drunk driving is a serious offense in Michigan. If you are convicted, the results can be devastating. In addition to jail time, or possibly prison time, there are very high fines and fees, loss of your license, probation, court costs, attorney fees, increased insurance costs, loss of your vehicle and a number of other penalties. These things can impact your ability to keep your job and the resulting loss of income will negatively impact your family.


All things considered, you are going to need a very skilled, very experienced DUI defense attorney working on your behalf, fighting to defend your rights and protect you from over-zealous prosecutors and police. That’s where we come in.


At The Kronzek Firm, we have decades of experience defending individuals accused of impaired driving, drunk driving, operating under the influence of intoxicants, and all other forms of alcohol related charges. So if you have been arrested and charged with a DUI, OWI, or OUIL, call us immediately at 866 766 5245. We can help.


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