Los Angeles DUI Chain of Custody

In order to prove that a defendant is guilty of a driving under the influence offense, the prosecution must be able to provide evidence of the defendant’s impairment. In DUI cases where the defendant did not refuse chemical testing, the prosecutor will introduce evidence relating to the breath test or blood test that was conducted by law enforcement. The breath test is conducted at the police station at the time of arrest and a result is available immediately. The blood test requires that a sample of the defendant’s blood be drawn and then sent to a laboratory where it is evaluated for the presence of alcohol or drugs. Because the blood test requires the transport and storage of a blood sample, there may be chain of custody issues that arise regarding this evidence that may be used to challenge the admissibility and authenticity of the blood sample.

The prosecution must be able to establish a complete chain of evidence regarding the blood sample to show exactly where the sample was at all times, from the time it was extracted from the defendant to the present. The prosecution would also have to show whose custody the sample was in and must be able to show that the sample was properly labelled and stored at all times.

Law enforcement agencies and crime labs often handle thousands of blood samples at any given time. There have been instances of blood samples being lost, comingled with other samples or switched. In order to maintain the integrity and admissibility of the sample, law enforcement must keep chain of custody records. These records can be requested by the defendant as part of the pre-trial discovery process and a review of these records may show irregularities that can be brought up in court.

The typical blood sample used in a DUI case is handled by several different people, including the arresting officer, the medical professional who conducted the blood draw, the officer in charge of transporting the sample and/or the defendant, the lab employee who is in charge of receiving and storing evidence, and the lab technician who was responsible for testing the sample. Each of these individuals may be required to testify regarding their role in handling the sample and can be questioned regarding the sample’s authenticity and any errors that may have occurred during the handling, storage or testing of the blood sample.

Whenever the sample has been moved between different parties, a chain of custody document must be signed and the date and time of receipt must be noted. This is done in order to ensure that the sample is always in someone’s care and that reasonable efforts have been made to prevent individuals from tampering with the sample.

The prosecution must also be able to establish that an accepted method of labelling and storing the blood sample was used. Usually, the sample must be labelled by the person who conducts the blood draw as soon as the blood sample has been extracted and placed in a vial. If the blood sample was not properly labelled at the time it was extracted, there may be an argument that the sample was mixed up with someone else’s blood sample and therefore did not belong to the defendant.

The prosecution must also be able to establish that the sample was properly stored at all times. In order to prevent blood fermentation, the blood sample must be kept refrigerated and also must contain a preservative. Usually sodium fluoride is added to the blood sample, however there is disagreement regarding how much sodium fluoride is necessary to ensure the integrity of the sample. Even in test tubes containing sodium fluoride, the bacteria Candida albicans has been found to exist. This bacteria is responsible for blood fermentation and the creation of alcohol in blood samples.

If you have been arrested for DUI and took a blood test, it is important that you speak with a Los Angeles DUI Lawyer right away. Lawyer Michael Kraut is a former Deputy District Attorney with over 14 years of prosecutorial experience who knows how to effectively fight chain of custody and other evidentiary issues.

For more information about Los Angeles DUI chain of custody, and to schedule your free consultation, contact Michael Kraut at the Kraut Criminal & DUI Lawyers located at 6255 Sunset Boulevard, Suite 1520, Los Angeles, CA 90028. Mr. Kraut can be reached 24/7 at 888-334-6344 or 323-464-6453.