Los Angeles DUI Chain Of Custody

  • May 24, 2017

    When a person is charged with driving under the influence, or DUI, the prosecution must produce evidence to demonstrate a defendant’s intoxication or impairment. Indeed, if a DUI case goes to trial, the prosecution must present evidence that convinces a jury beyond a reasonable doubt that the defendant was driving under the influence.

    If a person charged with DUI agreed to submit to chemical testing, the prosecution will have the results of that testing to use as evidence in the case. There are two types of chemical testing used in a DUI case. These are breath tests and blood tests.

    If a blood test is performed, a sample is taken from the person suspected of driving under the influence. That blood sample is then sent to a laboratory. At the lab, the blood sample is evaluated for the presence of alcohol or drugs.

    Due to the fact that the blood sample requires transport and storage for testing, the fact that the blood sample exchanges hands, may give rise to what legally are known as chain of custody issues. Chain of custody issues can be utilized by the defense to challenge the admissibility or even the authenticity of the blood sample in question.

    Establishing Chain of Custody

    In order to present evidence relating to a blood sample in a DUI case, the prosecution must establish what is called a chain of custody. In other words, the prosecution must demonstrate exactly where the blood sample was at all times and who had possession of it. The chain of custody must be demonstrated from the time the blood sample was drawn to its transport to a laboratory to its presence in the lab itself.

    The prosecution must be able to identify every person who had custody of, or contact with, the blood sample. In addition, the sample itself must be labeled and stored appropriately every step of the way.

    A DUI blood sample typically is handled by a number of people, including the arresting police officer, the medical professional who drew the blood sample, the office in charge of transporting the sample, and various people at the testing laboratory.

    Chain of Custody Document

    Each time a blood sample is moved, a chain of custody document must properly be completed and signed. This document must include specific information about the date and time of the receipt of the sample.

    Volume of Blood Samples

    The sheer volume of blood samples associated with DUI and other cases can be significant. Law enforcement agencies and testing laboratories can handle thousands of blood samples at any time. Considering the volume of blood samples alone, mistakes happen. This can include samples being lost, even temporarily. Samples can end up comingled or even switched with one another.

    Proper Storage of Blood Sample

    The prosecution must also be able to demonstrate that a blood sample has been stored properly throughout the process. A blood sample must remain refrigerated at all times, within a specific temperature range. The failure to properly store a blood sample can result in blood fermentation, which creates alcohol in blood samples, destroying the possibility for reliable testing. Other issues can arise as well.

    Los Angeles DUI Lawyers and Chain of Custody Defenses

    A Los Angeles DUI lawyer can advise a person charged with DUI more fully about chain of custody, and mounting a defense involving chain of custody issues. This defense, and other issues, can be discussed in an initial consultation with legal counsel. A lawyer will provide an evaluation of case at that time. As a matter of practice, a DUI lawyer typical charges no fee for an initial consultation with a prospective client.

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