There are three types of chemical testing: Breath, blood and urine. An experienced criminal defense attorney will know how to point out the legitimate reasons why a chemical test was faulty. A rising blood alcohol level may show that the B.A.C would have been under a .08 at the time of driving. There are also issues such as whether driving occurred within three hours of the chemical test, or whether the B.A.C. results were even accurate if there was drinking after driving. Finally, there must generally have been volitional movement of the vehicle before you can be charged with DUI in California. There are many ways for an experienced attorney to whittle away at the trustworthiness of the prosecution’s evidence and prevent them from meeting their burden of proof beyond a reasonable doubt regarding the chemical tests.
There are many reasons for falsely high breath tests. The 15-minute observation period mandated by Title 17 of the California Code of Regulations may not have been complied with, or the accused may have burped, regurgitated or vomited within 15-minutes of taking the test. Medical conditions (Gastro Esophageal Reflux Disease, Irritable Bowel Syndrome, or Acid Reflux Syndrome) or dental work (dentures or bridgework which may trap mouth alcohol) could account for an inaccurate test result. The breath sample could have been tainted with mouth alcohol or the breath-testing device may not have been operating properly. A qualified DUI defense attorney will check the calibration and accuracy logs for the machine to ascertain whether or not the results are accurate, and will confirm whether the officer even followed the training protocol.
The blood sample can be drawn or stored improperly, or it may be tainted with improper levels of preservatives, all of which can give a false B.A.C. result. If the blood test results are truly suspect, a blood-split should be done to confirm the results. Occasionally DNA testing will show that the blood sample does not contain the accuser’s blood!