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DUI Breathalyzer and Blood Tests

San Diego Blood and Breathalyzer Testing Attorney 

When San Diego drivers are stopped by the police on suspicion of DUI, they will typically be asked to submit to a series of roadside sobriety tests. The California Implied Consent law does not require one to participate in these roadside sobriety tests, but it does require one to submit either a breathalyzer or blood test - if lawfully arrested for driving under the influence of alcohol (blood or urine test in drug cases). Unfortunately, the results of breath and/or blood tests can be in error for a number of reasons.

Speak to a DUI Lawyer in San Diego As Soon As Possible

While urine testing is considered unreliable in drunk driving cases, it remains an acceptable test for drugs. Urine chemical tests may produce dubious results however, due to the fact that traces of drugs remain in the body long after their active effect has dissipated. Blood and urine testing can further involve problems stemming from laboratory procedure, instrument error, chain of custody, and reliability of witnesses. To learn more about this subject; the defense of a DUI case in San Diego, and DMV Hearings, call Mark R. De Yoe now at (619) 894-8295 or email him.

Problems with DUI Breath Tests

Breath testing is an indirect measurement of one's blood-alcohol content based upon their breath-alcohol content. California breath testing devices start with a legislatively imposed conversion ratio of 2,100 to 1 - in effect stating that a given subject's breath to blood ratio is universally the same as everyone else's. Unfortunately, this is simply not the case, and individual differences can result in higher than true blood-alcohol readings.  As recognized by the California Supreme Court in the July, 2009 case, People v. McNeal, different individuals have different partition rations, and a single individual's partition ratio can vary over the course of a day; all influenced by variables including body temperature, atmospheric pressure, medical conditions and more.  In recognizing these true scientific realities, the California Supreme Court in People v. McNeal, held that evidence about partition ratio variability is relevant in a generic DUI trial to rebut the presumption that a given individual is, "under the influence" if their breath test result was a .08%, or more.  This case made every experienced California DUI defense attorney very pleased.     

Additional problems with breath testing can come from a lack of specificity in testing, raw alcohol from the stomach or mouth, equipment problems, operator problems, and more. Moreover, the State of California has a number of strict laws specifically dealing with how a breath test is administered - to ensure accuracy. San Diego DUI defense attorney Mark R. De Yoe knows what to look for, and how to attack breath test results both in Court, and before the California DMV.

Blood and Urine DUI Testing Concerns

Blood testing can be inaccurate due to problems with the actual blood specimen itself.  Aside from this head on fact, if the blood is not properly drawn and preserved, significant errors may occur.  Blood can be re-tested however, by a highly respected, qualified, independent laboratory.  Sometimes a very accurate and precise re-test of a blood sample will indicate a significantly lower blood alcohol content.  The Law Office of Mark R. De Yoe, APLC, in San Diego, California, provides a valuable free initial consultation to discuss the facts surrounding your DUI case and possible defense strategies. We also provide experienced representation for court and DMV hearings involving driving while having a measurable blood-alcohol content of a .08%, or more. You can learn more by calling Mark R. De Yoe at (619) 894-8295 or you can contact him by email through this site.   

In a San Diego DUI case the key issue is what was one's blood alcohol content at the time of driving (not later, after shock, stress and excitement of being arrested for a DUI). One's blood alcohol rises and falls and this absorption is impacted by a number of factors from food intake to gender. There are a host of other problems surrounding blood testing as well. 

Serving these Cities in San Diego County

At The Law Office of Mark R. De Yoe, our DUI Attorneys will help defend you against any DUI charges in these San Diego cities:

  • Chula Vista
  • Pacific Beach
  • Ocean Beach
  • Point Loma
  • Mission Valley
  • El Cajon
  • La Mesa
  • National City
  • And all other cities in and around San Diego County
If you have been charged with a DUI and have taken a breathalyzer, blood, or urine test, call Mark R. De Yoe now at (619) 894-8295 or email him to discuss your case.