Problems with DUI Blood Tests 

blood being drawn from the inner arm

After arresting a driver for suspicion of driving under the influence (DUI), a police officer will administer a chemical test. Typically, it will be a blood test, a breath test, or a urine test. The results are then used to support your prosecution. Of these three tests, a blood test is considered to be the most accurate. However, this does not make them infallible. In fact, there are a number of reasons that a DUI blood test can result in a false positive. Greater Phoenix-area attorney James E. Novak is deeply familiar with the many factors that can taint chemical DUI tests. As a skilled DUI attorney, he will examine your arrest details for potential testing errors that can lead to charges being reduced or dismissed. His number one goal is to help you avoid the costly consequences of a DUI conviction. To learn more, contact our offices today.

Test Comparison

Blood, urine, and breath tests can all produce inaccurate blood alcohol concentration (BAC) results. Urine testing is considered to be the least reliable, followed by breath, then blood.

Urine Testing

Due to its inherent unreliability, urine testing is generally allowed only when blood or breath testing is not available. Like the breath test, urine testing does not actually measure BAC. Rather, it produces an estimate of alcohol in the blood based on its average presence in the urine. However, alcohol content in the urine can vary greatly from one person to the next. Results can also be affected by how recently urination has taken place, and whether any nonalcoholic liquids were consumed. Finally, as with all chemical testing, urine tests are subject to laboratory error.

Breath Testing

This test also produces an estimate of BAC based on an average. Since this can vary greatly among testing subjects, and even for the same person over time, false readings are not uncommon. Test results can also be affected by a long list of factors including health conditions, medications, presence of alcohol in the mouth, and use of breath fresheners. Improperly functioning testing equipment and procedural errors in testing are also possible.

Blood Testing

Most people assume that a DUI blood test is beyond reproach. On the contrary, there are several reasons a blood test can produce a false positive including: 

  • Presence of diabetes or high blood ketones
  • Use of herbal supplements or cough medicine
  • Alteration of alcohol content due to skin being swabbed with alcohol at the injection site
  • Other errors in blood collection that affect specimen integrity
  • Not using a properly trained, certified, neutral medical professional
  • Testing just the serum instead of the whole blood
  • Improper storage and maintenance of the sample
  • Chain of custody issues
  • Lack of sound scientific procedures by forensic labs

In short, there are a number of complex procedures that must be precisely followed in order for a blood sample to accurately reflect the actual BAC. If a sample was mishandled at any point, from the time it was taken through the reporting of the result, an attorney can have the evidence omitted due to a violation of chain of evidence procedures. Finally, probable cause had to exist for your blood to be tested in the first place.

Contact a DUI Expert

James E. Novak is an experienced, highly qualified DUI attorney with an outstanding track record and many satisfied clients. If you are facing a DUI case, he can help you take back control with a solid legal defense. To schedule a consultation, contact us today.

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