Chemical Evidence

Chemical Evidence

Chemical evidence is the most important part of the state’s case.  Your Orange County DUI attorney will review the standards and legal rules for the various chemical tests administered in DUI cases.  The results of such tests are admissible as evidence only if the tests were administered in accordance with the correct standards.  For instance, the admissibility of breath test results depends on the following:

Orange County DUI attorney


  • The qualifications of the officer who administered the test
  • The procedures used during testing
  • The precision of the machine used for testing
  • The records of maintenance, calibration, and repair of the machine used for testing


If urine or blood testing was conducted, both the certifications and qualifications of the technicians and of the laboratory itself must be examined, as well as the chain of custody of the sample.  Faulty testing procedures, inadequate technician training, failure to follow sample handling regulations, and improper facility inspections all provide the potential for error.  Equipment and reporting standards must be examined as well.


An excessively high and erroneous blood alcohol test can result if a swab containing alcohol was used at the puncture site where blood was taken.  This contaminated sample can lead to suppression of the evidence.


If your case involves urinalysis, your Orange County DUI defense lawyer will look into the possibility of challenging whether or not urinalysis is a reliable method of determining blood alcohol content.


If the arresting officer requested you to submit to a chemical test and you refused, your attorney will evaluate the impact of this refusal on your defense.  Even though the state may be hampered without chemical test evidence, the prosecution may be able to introduce as evidence the fact that you refused the test.  However, your Orange County DUI attorney may be able to demonstrate that you refused to take the test because of your desire to consult with counsel first.  If so, this can constitute a good faith refusal rather than a refusal to cooperate.


If you would like to discuss your DUI case with an Orange County DUI defense attorney, please call the Law Office of Mike Coffey Attorney at Lawand the Law Office of Mike Coffey Attorney at Lawat 800-706-7888.