abuse

When Drug Testing Is Asked to Prove More Than the Science Can Support

The limits of hair testing, laboratory interpretation, and the serious consequences of turning detection into conclusions about drug use, impairment, intent, or parental fitness.

Drug testing has become an accepted part of our courts, probation programs, workplaces, treatment programs, and child-protection system. Most of us see a laboratory report marked positive and assume the science has answered the question. But what question did it actually answer? That is what I began looking into, particularly with hair testing, and the deeper I looked, the more concerned I became about the difference between what a laboratory can detect and what courts, agencies, employers, and others may conclude from that detection. When a test result can affect someone’s freedom, employment, reputation, or relationship with a child, that difference deserves far more attention than it is receiving.

What Does a Positive Hair Test Actually Prove?

A laboratory can identify a drug or its metabolite in a biological sample. That is analytical detection. The problem begins when that finding is used to establish something much broader about the person being tested. A 2026 review published in Science & Justice concluded that hair analysis can establish exposure, but cannot accurately quantify dose or distinguish intentional ingestion from passive contact. Hair testing also does not establish current impairment simply because a substance is detected. Those are important distinctions because exposure, current drug use, impairment, intentional ingestion, and parental fitness are not interchangeable conclusions. If a test establishes exposure, then that is what the evidence should be called. The question is why we would allow anyone to claim it proves more.

The concern becomes greater when we look at what happens to the hair before the laboratory ever reports a result. Hair samples are washed in an effort to address external contamination, and a 2026 study comparing different decontamination procedures found that the procedure itself could materially change the THC concentration ultimately measured. Ten of the 58 positive specimens crossed from positive to below the reporting cutoff depending upon the washing procedure. Think about what that means. The person did not change. The hair specimen did not change. What changed was the laboratory procedure applied to that specimen, and in some cases the reported classification changed with it. If that result is later going to be used in a courtroom or by a government agency, how can the procedure that produced it be treated as an insignificant detail?

The Problem of Chemically Treated Hair

This raises another issue that I believe deserves considerably more attention, particularly when testing people who routinely dye, bleach, straighten, relax, or otherwise chemically treat their hair. A 2026 study involving 100 authentic drug-positive hair samples examined permanent dyes and bleaching and found changes in the measured concentrations of several drugs and metabolites. A separate 2026 case report examined corresponding hair segments from the same woman before and after permanent chemical straightening. The measured endogenous GHB concentrations increased approximately six to forty-three times in corresponding segments after treatment, while the measured alprazolam concentrations decreased.

That does not mean every chemically treated hair sample is inaccurate, and I am not suggesting that it does. What it does mean is that the physical and chemical condition of the hair can affect what is ultimately measured. The woman in that case did not somehow change what had happened during the period when the hair was growing. The hair was chemically altered, and the concentrations measured afterward were different. That leaves a very legitimate question when these tests are used to make serious decisions about another person: how much consideration is being given to the condition and treatment history of the hair before someone decides what those numbers supposedly mean?

A Laboratory Cutoff Does Not Establish Impairment

The reporting cutoff creates another opportunity for misunderstanding. Testing programs establish numerical thresholds for determining whether a specimen will be reported as positive or negative. Those thresholds serve an analytical and administrative purpose, but they are not biological lines separating an impaired person from an unimpaired person. A laboratory result crossing a reporting threshold does not, by itself, tell a court that someone was impaired while caring for a child or tell an employer that someone was impaired while working. The laboratory has reported that the measured concentration met its criteria for a positive result. Anything beyond that has to be supported by evidence capable of answering the additional question.

We have dealt with this problem before in another form. For decades, American courts have wrestled with the reliability and admissibility of polygraph evidence. I am not suggesting that a polygraph and a laboratory hair test are scientifically the same thing. They are not. The comparison is about the authority we sometimes give technology simply because the result looks scientific. A chart, a number, or a laboratory report can appear definitive while the conclusion someone wants to draw from it remains open to legitimate scientific challenge. Technology should strengthen evidence; it should not eliminate the responsibility to understand what that evidence actually proves.

When the Result Can Separate a Parent From a Child

The issue becomes much more troubling when a test result enters a child-protection or custody case. A mother may say she is not currently using drugs while a hair test reports a positive result. The report moves from the laboratory to a caseworker, from the caseworker to an attorney, and eventually into a courtroom. At that point, the consequences are no longer theoretical. Custody can be affected. Visitation can be restricted. A parent can find herself trying to prove that a laboratory report does not mean what everyone has already decided it means.

Before we reach that point, there are questions that should already have been answered. What period of hair was actually tested? Was the hair dyed, bleached, straightened, relaxed, or otherwise chemically treated? What decontamination procedure did the laboratory use? Was another type of biological specimen tested? Is there evidence of present impairment or current drug use independent of the hair result? These are not excuses for drug use. They are questions about evidence, and there is nothing unreasonable about demanding good answers before the government makes a decision affecting the relationship between a parent and a child.

There is also a federal policy question that cannot simply be ignored. As of 2026, mandatory federal workplace drug-testing guidelines cover urine and oral fluid, while federal hair-testing guidelines remain proposed rather than final. That does not establish that hair testing is unreliable or that it has no legitimate use. It does tell us that the standards governing its federal use have not reached the same status as urine and oral fluid. If those standards are still being worked through at the federal level, then I believe it is entirely reasonable to ask why a commercial hair-test result should enter another courtroom carrying the appearance that every question surrounding its interpretation has already been settled.

When Does This Become an Accountability Issue?

That is ultimately where this discussion leads me. Laboratories and testing companies know far more about these limitations than the average person being tested. They know how samples are washed. They know what cutoffs mean. They know external contamination has been an issue in hair analysis. They know cosmetic treatments can alter measured concentrations. They also know the difference between detecting a substance and establishing impairment. If those limitations are important enough to appear in scientific literature, they are important enough to be understood when the resulting report is used against another human being.

The same responsibility extends beyond the laboratory. A caseworker, employer, probation officer, attorney, expert, or court should not take a limited scientific finding and expand it into a conclusion the underlying test cannot establish. And when the limitations are known but the result is nevertheless presented as something more definitive than the science supports, the next question is accountability. Who knew about the limitation? What did the laboratory actually report? What was represented to the decision-maker? Was contradictory evidence considered? And if somebody lost a job, freedom, professional license, or relationship with a child because the science was overstated, who is responsible for the damage?

Drug testing has legitimate purposes, and nothing in this discussion changes that. What concerns me is the possibility that we have become so comfortable with the word positive that we have stopped asking what it actually means. Science should be used to establish facts, not to give assumptions the appearance of scientific certainty. When the consequences can change another person’s life, the distinction between those two things matters.

The question is not whether a laboratory found something. The question is whether the laboratory finding actually proves what someone is claiming it proves.

About the Author

Mike Morrison is the 2026 PBUS National Bail Agent of the Year, President of the Mississippi Bail Agents Association, and a nationally recognized bail educator, speaker, and criminal justice commentator. With more than 35 years of hands-on experience as a licensed Professional Bail Agent and owner of Mike Morrison Bail Bonding Company in Hattiesburg, Mississippi, he brings a practical, real-world perspective to discussions involving American legal history, institutional accountability, constitutional rights, public safety, technology, and public policy.

Morrison is recognized as a bail trainer by the Mississippi Judicial College and is a sought-after guest speaker for judicial, prosecutorial, and industry conferences across the country. He has presented before state judges, justice court clerks, prosecutors, attorneys general staff, and bail professionals nationwide. He also leads professional education and ethics programs for bail agents through the Master Class Bail Agent Series and other national training initiatives.

He has published nearly 200 articles examining the institutions, policies, and decisions that affect working Americans. His writing is grounded in decades spent inside courtrooms, jails, communities, and the criminal justice system, and his commentary has surpassed 1.75 million views across social media in 2026.

Independent, plain-spoken, and focused on accountability, Morrison writes and speaks about the intersection of government, liberty, public safety, professional responsibility, and the real-world consequences of public policy in Mississippi and across the nation.