Raleigh DWI Lawyer Offers Guidance on Blood Tests

If you have been charged with a driving while impaired (DWI) offense and the charging officer requested a blood sample from you, chances are your case falls into one of three categories:

  1. you were involved in an accident involving personal injury to yourself where you were transported to a hospital and breath testing equipment was not readily available, or you were unconscious and could not perform a breath test;
  2. the officer suspects that you were impaired by drugs rather than alcohol, or drugs in addition to alcohol; or
  3. you refused to submit to a chemical analysis of your breath and the officer obtained a search warrant from a magistrate for a blood sample.

Blood test cases present unique problems for the State of North Carolina in proving impairment. North Carolina law requires that the Defendant be informed of his or her implied consent rights with regard to the taking of the chemical test and also requires that a properly trained nurse or other personnel take the blood sample. Once the blood is drawn, it must be labeled and sealed properly, and subsequently stored in an appropriate manner before being taken to the lab for analysis.

Once at the lab, the blood is analyzed through gas chromatography utilizing a flame ionization detector and/or mass spectrometry. One vial of blood is tested; the other is kept in storage in the event that the Defendant wants his own separate analysis at an outside lab. Typically in drug cases, the lab can only detect the presence of a particular substance in the Defendants blood; unlike alcohol, the blood result cannot quantify the amount of the drug in the Defendant’s blood.

Many drugs break down through metabolic processes into other inactive compounds after remaining in the body a short period of time. For instance, a blood result showing the presence of an inactive metabolite of marijuana can only show that the Defendant has ingested some amount of marijuana within the last approximately 30 days. It would not show that the Defendant was necessarily under the influence of the active compound, THC, at the time that he or she was operating the motor vehicle.

The complex issues involved with driving while impaired blood test cases make them often winnable cases. If you would like a free consultation, contact us or call at (919) 832-0307.