Skip to Content

Re-Analysis of Blood Test Evidence


Following an arrest for DUI in California, a suspect has the choice of whether to consent to a breath or a blood test. A breath test does not allow for independent testing on a future date as the breath testing machine does not retain a sample of breath for later re-testing. However, if a blood test is taken the regulations governing blood alcohol analysis require that enough blood be drawn from the suspect to allow for later independant testing.

In order to re-analyze a blood sample, it is necessary for defense counsel to prepare a blood split order and request that the judge sign the order. The signed order must then be forwarded to an independent toxicologist. The toxicologist working with defense counsel will then serve the order on the law enforcement agency keeping custody of the sample. The agency will then return the sample to the county crime laboratory for a "split" of the sample. A sufficient portion of the sample is then made available for collection by the toxicologist retained by defense counsel.

The independent toxicologist will then perform a duplicate analysis on the sample following the exact same procedure followed by the county crime lab. Normally, the toxicologist will also check to see if the sample contained a sufficient amount of preservative. It is also possible to perform a bacterial culture on the sample to see if there has been any bacterial growth in the sample that would cast doubt on the samples integrity and therefore on the blood alcohol results. Theoretically, a proper chain of custody, adequate preservative and proper refrigeration should maintain the samples integrity, but we have observed bacterial growth in samples despite these safeguards.

Most blood alcohol results turn out to be accurate, but some re-tests turn up surprising results that help in getting DUI charges dismissed. The bottom line is that you never know until you re-test. Defending a DUI in Los Angeles is often about digging for problems and issues and not just relying on the evidence presented by the prosecution.

If you have been arrested for a DUI and you are concerned about the accuracy of the blood test in your case, please contact Los Angeles and Orange County DUI lawyers Gold & Witham for a free case evaluation.