A blood alcohol concentration (BAC) is defined as the number of grams in every 100 milliliters of blood.  A person that is shown to have a BAC of 0.08 will have 0.08 of pure ethanol in any blood sample that equals 100 milliliters. BAC Test Validity In most DUI cases, the amount of alcohol in the blood stream is a secondary concern when a test is given.  The main interest of law enforcement is the amount of alcohol that has been absorbed into the brain.

This affects the ability to make sound judgments, ability to coordinate, and operate a vehicle. When it comes to measuring the amount of alcohol in the bloodstream, or breath, there is no practical way to go about this.  The reason is that the bones, brain, and fatty tissue contain less water than blood.  Therefore, to test anything other than the person’s blood may not give accurate results. When you are stopped in the state of Colorado, you have a choice between a blood test, breath test, or you may refuse.

A certified phlebotomist, who will use a “DUI Blood Kit” to prepare the arm and draw two vials of blood, gives a blood test.  One vial will sent to the State for further testing and the other vial may be sent to an independent laboratory if you choose to have the sample retested. It is preferred that blood alcohol tests are performed using whole blood as opposed to blood serum, which can give inaccurate results (up to 33% higher).

However, because blood serum gives faster results, hospitals will use their in their testing.  They also may use an alcohol swab to prep the site but this may contaminate the results. The process of blood testing has many areas to challenge ranging from the type of blood kit, the qualifications of the person taking the blood, the preparation for taking the blood, the handling  of the blood sample, storage of the blood sample and these sources of error occur before the blood sample has even reached the laboratory for testing.

Once at the laboratory, the testing process is filled with sources for error including the storage of the sample, the handling of the sample, preparing the sample for testing, the testing of the sample and use of known values, the recording of the sample and calculations pertaining to the results and the software used to determine the result.  A careful analysis of these process is often necessary to defend your case. There are many factors that affect the validity of blood alcohol testing and how the body processes alcohol, blood tests are not a full proof method to determine impairement.  A Colorado DUI lawyer can give scientific insight as to how blood test results may be challenged in court.