Former APD Lab Analyst Reports Problems with DWI Blood Testing

Last week, Debra Stephens, a former employee of the Austin Police Department Crime Laboratory reported her concerns about APD’s Blood Alcohol Laboratory’s testing process. Specifically, she claims that there are errors in the uncertainty budgets and reporting methods used by APD.

Austin DWI Lawyer


The letter states that APD’s Crime Lab is incorrectly reporting results using a statistical approach not used by other forensic laboratories. She states that their method validation procedure and estimation of measurement uncertainty has been incorrectly determined and reported. She writes that APD’s application of measurement uncertainty does not follow the guidelines recommended by ASCLD-Lab and she states that APD is simply not following acceptable scientific protocol in their procedures for reviewing and accepting analytical results. Ms. Stephens reports that APD is incorrectly reporting analytical results used in the prosecution of thousands of cases.

My office is in the process of corroborating Ms. Stephens findings with an independent scientific lab.

Ms. Stephens’s letter was sent to the Travis County District Attorney’s Office just as concerns have been raised recently about APD’s inability to care for and control DNA blood samples. APD has temporarily suspended operations at its DNA lab because of concerns raised by the Texas Forensic Science Commission. The commission raised concerns about calculations and formulas the lab was using in conducting DNA analysis. Travis County prosecutors have joined a statewide effort to re-evaluate cases affected by the miscalculations. But the Austin Police Department’s crime lab, which will have to recalculate statistics on about half of the 1,297 Travis County cases identified so far, is still validating new software and updating its protocols.

Although APD did not specify the standards in question, the FBI had announced they had corrected and updated their allele frequency data to all CODIS laboratories in the nation. However, those data brought an unexpected result: the Combined Probability of Inclusion and Combined Probability of Exclusion (CPI and CPE, respectively) could have changed – and changed significantly, in some cases.

Austin DWI lawyer

Austin DWI lawyer

Austin DWI lawyer

Austin DWI lawyer

Leave a Reply

Your email address will not be published. Required fields are marked *