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How Accurate are Texas DWI Blood Tests?

An instrument, or machine, specifically – the gas chromatograph, requires validation before labs may use it for reporting forensic blood results. ANSI/ASB 036 sets forth standards that serve as a minimum for ensuring that a machine can produce accurate results.  The most frequent issue I have run into with my cases when an expert analyzes the discovery is lack of proper validation on the machine. For example, it cannot properly account for matrix effects because the validation test use aqueous solutions versus blood. This is like comparing apples to oranges.

ANSI/ASB 054 sets forth minimum standards for quality control.  It specifically states that matrix-matched controls shall be used 054 (6.1). Once again, calibration on blood is required versus aqueous solutions.  Many north Texas crime labs are calibrating with aqueous solutions when they should be using blood. An Austin Texas DPS study reported an approximate difference of 20% when using aqueous versus blood solutions.

How reliable is Texas DPS in safeguarding forensic integrity? Well, it certainly was not forensically advisable for the lab to report results from tubes that lacked the required preservative, yet they did.

It is time for judges to hold laboratories accountable to the standards they must follow. Unfortunately, it has been my experience that some judges do not do this.  Judges are the gatekeepers of law and the standards.  You can’t expect laboratories to comply with requirements if they can get away without it.

There are many issues in Texas DWI blood tests that deserve investigation. Over 28 years, Mimi knows what to look for and how they affect your case.[/vc_column_text][/vc_column][/vc_row]