Laboratory Allegedly Mishandles DWI Blood Samples, Calling Multiple Cases Into Question

A private laboratory testing company contracted by Texas prosecutors reportedly mishandled paperwork related to blood samples intended for use in driving while intoxicated (DWI) cases. The extent of the company’s alleged error remains unknown, but it has prompted the district attorney’s office to state that the samples may have to be re-tested. Blood samples are used in DWI cases to establish the concentration of alcohol in a defendant’s bloodstream, known as blood alcohol content (BAC). The statute defining the offense of DWI does not require BAC evidence; however, it is generally the simplest way for the state to prove intoxication. Compromised blood samples could seriously hinder the state’s prosecution of many of the affected DWI cases.

The Bexar County District Attorney’s Office, which handles criminal cases in San Antonio and surrounding areas, contracts with a company in the Dallas/Fort Worth area to test blood samples taken in DWI cases. In approximately mid-May 2014, the office reportedly received a letter from the lab stating that “some paperwork was mishandled.” The office has not publicly stated exactly how many cases were affected, or exactly how, but news media have reported that the lab fired an analyst for multiple paperwork errors, including one incident involving about 350 incorrectly-labeled blood samples. The lab is reportedly conducting an internal investigation.

The DA’s office was reportedly receiving test results containing caveats from the lab that they could not say for certain which sample produced the results. Other documents reportedly referenced contaminated lab equipment, although the DA’s office has stated that they do not believe any blood samples were contaminated. Defendants currently involved in DWI cases in San Antonio, along with their advocates, are not very reassured by the DA’s statements.

Under Texas law, BAC is not the only standard for determining intoxication, but it is often the simplest for the state to prove. “Intoxication” is presumed if a person’s BAC is 0.08 percent or more, but the state may also present evidence that a defendant lacked “the normal use of mental or physical faculties” because of alcohol or drugs. Tex. Pen. Code §§ 49.01(2), 49.04. Under Texas law, a driver suspected of DWI is presumed to have consented to blood testing, and may face license suspension for refusal. Tex. Transp. Code §§ 724.011, 724.035. Proving intoxication without BAC evidence requires eyewitness testimony, usually from an arresting officer.

A defendant can challenge BAC evidence based on factors that exist entirely outside of the courtroom, like the condition of the testing device or possible contamination of a sample. Eyewitness evidence of intoxication requires the witness to recount the incident in the courtroom in front of the judge or jury, leaving the witness open to cross-examination by the defendant. Prosecutors generally prefer to have BAC evidence to support their accusations. This is not to say that a prosecutor will not pursue a DWI case in the absence of BAC evidence, but it will be interesting to see how these cases in San Antonio proceed.

For more than twenty years, board-certified criminal defense attorney Michael J. Brown has represented the rights of the people of west Texas in criminal cases. He draws on his experience as an FBI agent and a prosecutor to assist clients charged with alleged state and federal offenses related to drugs, white collar crime, and other matters. To schedule a confidential consultation to discuss your case, contact us today online or at (432) 687-5157.

More Blog Posts:

Texas Police Arrest Man for DWI, Despite Negative Breath and Blood Tests, Texas Criminal Lawyer Blog, March 9, 2014
DUI Arrest Demonstrates How “Civil” Penalties May Result from Criminal Cases, Texas Criminal Lawyer Blog, June 11, 2013
Warrantless Blood Tests in DWI Investigations Under Review by U.S. Supreme Court, Texas Criminal Lawyer Blog, January 11, 2013

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