Grand Rapids Blood Testing in DUI Cases

In Michigan, you may be arrested for driving under the influence (DUI) if your bodily alcohol content (BAC) is over .08%. To determine your BAC, one of three tests may be administered: blood, breath, or urine. If you have recently been charged with DUI after failing the Michigan blood test, you should speak with an experienced Grand Rapids DUI lawyer as soon as possible.

Of the three tests, the blood test, is considered the most accurate; however, it is not the most practical. Blood must be drawn by a professional in a hospital or clinic setting and specific guidelines must be followed to ensure the sample is not contaminated. Often a warrant is required to draw blood too, and for these reasons, most police officers favor asking for a breath test. An officer can request a blood test too, and if you refuse either request, according to Michigan's Implied Consent Laws, the officer can obtain a warrant to force you to give a blood test.

Several different methods can be used to test blood. Generally, if the driver's blood is being tested to determine how much alcohol is in his or her system, headspace gas chromatography is used for analysis. This method involves an instrument called a gas chromatograph, which separates and measures the alcohol in the blood. This is the preferred method employed at the Michigan State Police Toxicology crime lab where your blood will be tested.

To administer this test, the analyst draws the driver's blood and places it into a "headspace" vial, with a small amount of a kind of alcohol that serves as a reference. This headspace vial is inverted several times to mix the blood with the chemicals and then heated to produce gas. This "headspace" gas is then extracted and put into a thin capillary column. Another gas, such as helium, is used to push the headspace gas up the column. During this test, the temperature must remain consistent to produce accurate results.

When it gets to the end of the column, the gas reaches a flame ionization detector. The flame incinerates the chemicals and produces ions as the result of an electrical charge. These ions are then measured and used to determine the driver's blood alcohol level. This is called the quantitative analysis. The qualitative analysis, which answers what kind of chemical is producing the ions, is determined by the "retention time" meaning how long the molecules take to traverse the capillary column and reach the flame ionization detector. The gas chromatography does not actually test the blood—it is an indirect test, like the breath test. However, blood testing is generally accepted as more precise and accurate than breath testing.

As you can probably tell, blood testing is a complicated process. You need an experienced DUI lawyer who understands the Michigan blood test. The DUI lawyers at the Barone Defense Firm are some of the state's leading experts on blood testing, and will be able to thoroughly analyze the blood test results in your case to determine if they are accurate, precise and most importantly, reliable. If not, then we will ask the judge to throw the test results out of evidence, effectively winning your case. For a free DUI case evaluation and a copy of The Michigan DUI Book (A Citizen's Handbook on Fighting a Michigan DUI Case), contact The Barone DUI Defense Firm today.