Legal Alcohol Driving Limit

Blood Test Drunk Driving | Michigan DUI Attorney

Blood Alcohol drunk driving, BAC legal limitWhen investigating a possible case of driving under the influence, the police may ask you for a sample of your breath or blood. Breath testing remains the most common type of chemical testing, but DUI blood tests are becoming more common.

If your blood is taken by law enforcement the purpose is to test if for alcohol or drugs. DUI cases involving blood are considered by most DUI lawyers to be more difficult to defend because blood test results are considered to be a more reliable.

Your defense lawyer must understand how a blood test works and how it is analyzed in order to fully represent your interests and rights .

The Following is a Summary of How your Blood Sample will be tested for Blood Alcohol Content:

Transportation of the blood sample – after the blood is drawn, the blood sample will usually be sent by first class mail to the Michigan State Police (MSP) Forensic Lab. This lab is located in Lansing. This is where most blood samples in DUI cases are tested.

However, if you were arrested for drunk driving in Oakland County Michigan, then you blood might be tested at the newer lab run by the Oakland County Sheriff. Your blood sample may well be tested in this newer lab if your DUI case in any of Oakland County’s most common District Courts, including:

  • 52-1 District Court located in Novi Michigan
  • 52-2 District Court located in Clarkston
  • 52-3 District Court located in Rochester/Rochester Hills
  • 52-4 District Court located in Troy Michigan
  • 48th District Court Located in Bloomfield Hills
  • 44th District Court Located in Royal Oak

Storage of the blood sample – the kit is received by MSP, documented by a lab tech, and stored in their temperature controlled storage room. The tubes are also presumed to contain a known amount of preservative and anti-coagulant both in an effort to maintain the integrity of the sample. Therefore, even at this stage, the State does not have your blood but a mixture.

Preparation of blood sample for testing – a Lab Analyst will obtain this mixture when they are prepped to run it through a Head Space Gas Chromatograph, and again alter the mixture to something new. First, the Lab Analyst will take some of the mixture and pour it into a new vessel or tube.

Then the technician will use a syringe like device called a pipette to withdraw an amount of that mixture. This mixture and put it into a new tube, that also includes an internal standard. The internal standard is a kind of alcohol.

The reason for two separate tubes is because the sample will be run through two identical yet separate machines. Now there will be two tubes, each including the mixture plus a new volatile, which will act as an internal standard.

Testing of the blood sample for alcohol or drugs – the next step is to heat this mixture. The mixture prepared by the technician includes your blood, the two chemicals from the original tube, the new internal standard alcohol. This tube is heated in order to reach a partition or equilibrium. The idea is that the amount of analyte in the gas above the liquid represents a known correlation of the analyte in the mixture.

In Michigan, the process is automated, which means that a pipettor automatically withdraws or siphons an amount of the head space, or gas, from the heated mixture and will inject it into the gas chromatograph through the injection port. Once injected a carrier gas is needed in order to move the volatile gas through the machine.

The column is located in the oven of the machine, which will be heated to a constant temperature. The column is to slow down certain analytes wherein there will be an expected time the analyte will exit the column.

At the end of the column, the volatile is introduced to an FID or a Flame Ionization Detector, wherein the FID passes the sample and carrier gas (and whatever is coming through the column) through a hydrogen air flame.

barone-1-300x278The FID burns the organic compounds that pass through which create increased ions. A polarizing voltage attracts these ions to a collecter located near the flame. The current produced is proportional to the amount of the sample being burned. This current is sensed by an electrometer, converted to digital form, and sent to an output devise, which ultimately creates the chromatograms that defense counsel have an opportunity to review.

Measuring the alcohol or drugs in the blood sample – the chromatograms, specifically the subject sample, will indicate the two peaks that have been created. One peak will be the known volatile, the internal standard, wherein there is an expected time it will pass through the machine and also a known amount that will be measured by determining the area contained under the peak.

The other peak will be the believed ethanol alcohol, wherein the level will be determined by measuring the area under the peak. Again, this is a comparative analysis. The calculation that is ultimately made is based upon the software attached to the machine, which is unknown, even to the State, but will result in a measurement of ethanol alcohol in units of grams alcohol per 100 milliliters of blood.

Finding a Top DUI Lawyer in Michigan

Start with a search of the terms “top DUI lawyer near me.” Then, be sure you ignore all the lawyers who pretend they are experts based on bogus credentials. If you have an intoxicated driving case that involves a blood draw you must be confident that your DUI defense counsel has a deep understanding this complex process of blood testing.

The drunk driving defense lawyers at the Barone Defense Firm offer a free consultation. Call us today and learn how your DUI can be defended.

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