In Michigan, you may be arrested for driving under the influence (DUI) if your blood alcohol content (BAC) is over .08%. In order 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 scientific; 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.
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.
To administer this test, the analyst draws the driver’s blood and places it, with a small amount of a chemical, into a vial. This vial, referred to as a “headspace” vial, is shaken to mix the blood with the chemicals and then heated in order to produce gas. This “headspace” gas is then extracted and put into a thin column. Another gas, such as helium, is used to push the headspace gas up the column. During this test, the temperature must remain consistent in order 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. The gas chromatography does not actually test the blood—it is an indirect test, similar to 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. 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.