PASSAGE OF THE DAY: "In April 2025, The Guardian reported that Quest Diagnostics used an “alternative reagent” in thousands of urine drug screens conducted within California prisons (https://www.theguardian.com/us-news/2025/apr/09/california-prison-drug-tests). This change, made without sufficient external disclosure, resulted in a dramatic spike in presumptive positive tests for opiates—tripling the usual rate. More than 5,000 incarcerated individuals may have been affected, many of whom were denied parole or had progress in rehabilitation programs questioned based on unconfirmed results. While Quest acknowledged the reagent caused higher presumptive positives, they downplayed its impact and failed to alert those most directly harmed by the error. It also begs the question: was this “alternative reagent” used by Quest Diagnostics outside the California prison systems? This incident highlights a critical and ongoing issue across legal systems nationwide: presumptive drug tests, commonly immunoassays, are not definitive."
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POST: "False Positives, Real Consequences: What the Quest Diagnostics Issue Reveals About Drug Testing Failures," Guest Posts: Dr. Korin Leffler, PhD, MSEH – Expert Pharmacologist & Toxicologist; Dr. Rohan Parekh, PhD – Expert Pharmacologist, Chemist & Toxicologist. Published by "Forensic Resources' on April 30, 2025. (The Office of Indigent Defense Services provides assistance to North Carolina attorneys litigating complex scientific evidence through its Forensic Resource Counsel.)
GIST: "In April 2025, The Guardian reported that Quest Diagnostics used an “alternative reagent” in thousands of urine drug screens conducted within California prisons (https://www.theguardian.com/us-news/2025/apr/09/california-prison-drug-tests). This change, made without sufficient external disclosure, resulted in a dramatic spike in presumptive positive tests for opiates—tripling the usual rate. More than 5,000 incarcerated individuals may have been affected, many of whom were denied parole or had progress in rehabilitation programs questioned based on unconfirmed results. While Quest acknowledged the reagent caused higher presumptive positives, they downplayed its impact and failed to alert those most directly harmed by the error. It also begs the question: was this “alternative reagent” used by Quest Diagnostics outside the California prison systems?
This incident highlights a critical and ongoing issue across legal systems nationwide: presumptive drug tests, commonly immunoassays, are not definitive. These tests rely on antibody-based detection of drug classes and are highly susceptible to cross-reactivity with structurally similar legal substances—such as certain antibiotics, antidepressants, decongestants, or even food products like poppy seeds. Without confirmatory testing using mass spectrometry-based platforms like GC/MS or LC/MS, which precisely identify the chemical structure of specific drugs, these preliminary tests can—and often do—yield false positives. Yet in many criminal, family court, and probation contexts, these unconfirmed results are treated as conclusive evidence of drug use.
Scientific and forensic standards are clear: presumptive tests are screening tools, not diagnostic endpoints. They are intended only to flag specimens for further analysis, not to serve as a basis for legal action. Best practices outlined by the Substance Abuse and Mental Health Services Administration (SAMHSA) and the U.S. Department of Health and Human Services mandate confirmatory testing before a result can be reported as positive in workplace or federal testing programs. The failure to apply this same rigor in legal settings places individuals at serious risk of wrongful punishment or separation from their families—based on nothing more than a preliminary indication.
The real-world consequences of relying on unconfirmed test results are profound. A single presumptive positive can result in incarceration, the loss of child custody, employment termination, or reputational damage. In our work as pharmacologists and forensic toxicologists, we’ve encountered numerous cases where legal outcomes hinged on a test result that was never scientifically validated. This is not merely a technical oversight—it is a systemic failure to safeguard due process using reliable, evidence-based science.
If you are an attorney, public defender, or legal professional navigating a case involving drug testing results, we encourage you to engage an expert early. Understanding the difference between a presumptive screen and a confirmed analytical finding can dramatically shift the narrative of a case. Don’t let a flawed reagent or a misunderstood report dictate the outcome. Accurate interpretation matters—because liberty, family, and fairness depend on it."
The entire post can be read at:
PUBLISHER'S NOTE: I am monitoring this case/issue/resource. Keep your eye on the Charles Smith Blog for reports on developments. The Toronto Star, my previous employer for more than twenty incredible years, has put considerable effort into exposing the harm caused by Dr. Charles Smith and his protectors - and into pushing for reform of Ontario's forensic pediatric pathology system. The Star has a "topic" section which focuses on recent stories related to Dr. Charles Smith. It can be found at: http://www.thestar.com/topic/charlessmith. Information on "The Charles Smith Blog Award"- and its nomination process - can be found at: http://smithforensic.blogspot.com/2011/05/charles-smith-blog-award-nominations.html Please send any comments or information on other cases and issues of interest to the readers of this blog to: hlevy15@gmail.com. Harold Levy: Publisher: The Charles Smith Blog.
SEE BREAKDOWN OF SOME OF THE ON-GOING INTERNATIONAL CASES (OUTSIDE OF THE CONTINENTAL USA) THAT I AM FOLLOWING ON THIS BLOG, AT THE LINK BELOW: HL:
https://www.blogger.com/blog/post/edit/120008354894645705/4704913685758792985
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FINAL WORD: (Applicable to all of our wrongful conviction cases): "Whenever there is a wrongful conviction, it exposes errors in our criminal legal system, and we hope that this case — and lessons from it — can prevent future injustices."
Lawyer Radha Natarajan:
Executive Director: New England Innocence Project;
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FINAL, FINAL WORD: "Since its inception, the Innocence Project has pushed the criminal legal system to confront and correct the laws and policies that cause and contribute to wrongful convictions. They never shied away from the hard cases — the ones involving eyewitness identifications, confessions, and bite marks. Instead, in the course of presenting scientific evidence of innocence, they've exposed the unreliability of evidence that was, for centuries, deemed untouchable." So true!
Christina Swarns: Executive Director: The Innocence Project;
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SEE BREAKDOWN OF SOME OF THE ON-GOING INTERNATIONAL CASES (OUTSIDE OF THE CONTINENTAL USA) THAT I AM FOLLOWING ON THIS BLOG, AT THE LINK BELOW: HL:
https://www.blogger.com/blog/post/edit/120008354894645705/4704913685758792985
———————————————————————————————
FINAL WORD: (Applicable to all of our wrongful conviction cases): "Whenever there is a wrongful conviction, it exposes errors in our criminal legal system, and we hope that this case — and lessons from it — can prevent future injustices."
Lawyer Radha Natarajan:
Executive Director: New England Innocence Project;
—————————————————————————————————
FINAL, FINAL WORD: "Since its inception, the Innocence Project has pushed the criminal legal system to confront and correct the laws and policies that cause and contribute to wrongful convictions. They never shied away from the hard cases — the ones involving eyewitness identifications, confessions, and bite marks. Instead, in the course of presenting scientific evidence of innocence, they've exposed the unreliability of evidence that was, for centuries, deemed untouchable." So true!
Christina Swarns: Executive Director: The Innocence Project;
