Kaitlin spent the first weeks of her newborn son’s life in a panic. The hospital where she gave birth in October 2022 had administered a routine drug test, and a nurse informed her the lab had confirmed the presence of opiates. Child welfare authorities opened an investigation.

Months later, after searching her home and interviewing her older child and ex-husband, the agency dropped its investigation, having found no evidence of abuse or neglect, or of drug use.

The amount of opiates that upended Kaitlin’s life — 18.4 nanograms of codeine per milliliter of urine, according to court documents — was so minuscule that if she were an Air Force pilot, she could have had 200 times more in her system and still have been cleared to fly.

But for Kaitlin, the test triggered an investigation with potentially life-altering consequences. (ProPublica is using Kaitlin’s first name because her full name has been redacted from court documents. She declined to be interviewed for this story.) 

The ordeal “tempered what was otherwise supposed to be a joyous occasion” for the family, according to a lawsuit filed in 2024 by New Jersey’s attorney general against the hospital system, Virtua Health.

The hospital said in a statement that it has “a relentless commitment to evidence-based, equitable care for every family.” In court documents, it denied the lawsuit’s allegation that it discriminated against pregnant patients and noted that Kaitlin consented to the test. It also said that New Jersey law mandates it to submit reports of “substance-affected infants” to the state’s Division of Child Protection and Permanency. The lawsuit is pending and a judge has referred it to mediation.

Drug-testing labs typically report results in black and white: positive or negative. But a little-known fact about the industry is that those results are often based on standards that are wholly discretionary. For example, nearly all states use a threshold of 0.08% blood alcohol content to decide if a motorist is intoxicated. But for other drugs detected in urine, saliva and hair, cutoff levels vary from test to test and lab to lab — including Kaitlin’s test for opiates.

There’s no consensus among labs on what level should confirm the presence of codeine in urine, said Larry Broussard, a toxicologist who wrote an academic journal article on “growing evidence” that poppy seeds in bagels and muffins provoke positive test results. (Kaitlin ate a bagel shortly before taking her drug test, according to court documents.) There’s more consensus for some other drugs, but labs still disagree on appropriate cutoff levels for common drugs such as THC (the compound in marijuana that creates a high) and meth, said Broussard.

In 2022, the same year Kaitlin tested positive for codeine, the Department of Defense noticed a surge in personnel on military bases blaming positive tests on poppy seeds. Scientists at the military’s labs concluded that a change in the manufacturing process of some poppy seeds had led to contamination, causing service members to be falsely accused of abusing drugs.

So far, 62 positive tests for codeine have been “overturned and adjusted in Army records,” an Army spokesperson told ProPublica. In response, the Department of Defense in March 2024 doubled the military’s cutoff level for codeine tests to avoid false positives triggered by poppy seed muffins, bagels and other foods. Service members are now cleared for duty with up to 400 times more codeine in their urine than is used to justify child welfare investigations in some states, ProPublica found.

ProPublica reviewed cutoff levels used to confirm the presence of common drugs, including opiates, meth, THC and cocaine, as cited in court records, labs’ contracts with government agencies and scientific journals, as well as in interviews with toxicologists. We found that the cutoff levels used by the child welfare systems vary widely from jurisdiction to jurisdiction. One large state agency, Michigan’s Department of Health and Human Services, contractually required a lab to use levels that it later acknowledged were “scientifically unsupportable.” 

Ted Simon, an expert toxicology witness and a board member of the nonprofit Center for Truth in Science, which advocates for objectivity in research, said agencies are better off consulting with labs to set cutoff levels. That’s because “some labs do validation testing to ensure the accuracy of their cutoffs based on knowledge of human biology.” But even when labs set levels, they don’t always get them right. Some labs “just use the sensitivity of the chemical analysis to measure vanishingly tiny concentrations with no way to assess the relevance to humans,” Simon said. This can result in situations like Kaitlin’s, where the hospital’s cutoff was near the lower limit of what sophisticated lab instruments can detect, he said after reviewing her case.

Meanwhile, “labs tell their clients what they want to hear and are hesitant to disclose the uncertainty inherent in their methods,” Simon said.

There’s no industry consensus on what, or if anything, should be done about the differing standards. Some experts see a need for uniform levels but acknowledge it would require lengthy vetting before toxicologists and other stakeholders agree on what’s appropriate. Others maintain that as long as labs are transparent and support their decisions with research, they should continue choosing their own levels. “The labs do what works for the instruments that they have,” said Simon.

Child welfare agencies employ a patchwork of drug testing standards, according to contracts and procurement documents.

Some, like Los Angeles County’s Department of Children and Family Services, require labs to use high cutoff levels that protect against false positives. Other agencies’ contracts with their drug testing services do not specify cutoff levels, leaving the decision to the lab.

A few large agencies require labs to use ultra-low levels, which catch more users but come with risks. Incidental exposure to a substance in the environment and over-the-counter medications can trigger positives. “The smaller the concentration that you try to detect, the more likely you are to get false positive results,” said toxicologist Paul Cary, who wrote a guide to testing for drug courts, which aim to address the addictions of people accused of drug-related crimes and avoid incarceration.

Some Child Welfare Agencies’ Thresholds for a Positive Drug Test Are Lower Than the Federal Government’s

The levels at which various agencies consider a drug test positive for meth vary widely. “The smaller the concentration that you try to detect, the more likely you are to get false positive results,” said toxicologist Paul Cary.

250 ng/ml
meth

125 ng/ml

100 ng/ml

0

Federal workers cutoff

Los Angeles County Dept. of Children and Family Services

Orange County, California, Social Services Agency

Utah Division of Child and Family Services

Georgia Division of Family and Children Services

Less meth needed to trigger positive result
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The federal government sets standards for drug testing 14 million people. These include public-sector employees as well as workers whose performance affects the safety of others, known as safety-sensitive roles, like airline pilots, truck drivers and those working in nuclear facilities. For decades, the program was known for a rigorous scientific review and inspection process to ensure accuracy. 

In 2025, President Donald Trump’s second administration overhauled the Substance Abuse and Mental Health Services Administration, the federal agency responsible for the testing standards program, and dismissed half of its staff. It also disbanded the expert panel that proposed scientifically valid cutoff levels, the Drug Testing Advisory Board. “There could be issues for national security or safety sensitive issues that might be impacted given the recent changes,” said Hyden Shen, former regulatory and policy oversight lead at the health agency’s division of workplace programs. In the spring, Shen resigned alongside almost half of his division. He spoke to ProPublica after leaving federal employment.

Private labs have long been free to set their own standards, independent of the federal government’s recommended levels. The CEO of a laboratory company specializing in testing for probation departments, child welfare agencies and courts testified in a lawsuit that in 2018 the lab had lowered cutoff levels for cocaine in hair follicle tests by a factor of five without amending its contract with the state child welfare agency. The company said that the change was to align its levels with scientific updates and that state agencies were made aware of the new cutoffs when it reported test results. The lawsuit was settled with the lab denying wrongdoing.

Federal workers who test positive for drugs can’t be punished until their results are scrutinized by medical review officers, physicians who verify that positive drug test results aren’t being triggered by legitimate medications. (For example, without a special follow-up called an isomer test, over-the-counter Vicks VapoInhaler is indistinguishable from street drugs in multiple types of drug tests.) But medical review of test results is expensive, and few state agencies require it for child welfare cases or for testing people on probation. One lab competing for a contract to test probationers and juveniles in a residential facility in Kansas discouraged the use of medical review officers, saying it would “result in extra expense and extra time for results delivery.” Other state agencies, especially those that oversee parole, probation or prisons, skip confirmation testing entirely and rely instead on cheaper, less accurate immunoassay tests, unless someone contests their result and can afford to pay out of pocket for a follow-up, according to contracts between state courts and labs. 

Agencies “are effectively saying, ‘Most of these people probably did use drugs. And, yeah, OK, there’s a handful that didn’t. But it would bankrupt us to have to confirm all of these,’” said Karen Murtagh, executive director of Prisoners’ Legal Services of New York, which has represented inmates in drug testing cases.

In the spring of 2019, Marie Herrera was working to reunite with her four kids in Michigan’s foster care system. (ProPublica is referring to Herrera by her middle name at her request, to maintain her privacy as she moves forward with her life.) At a hearing on her case, a foster care worker testified that it was going well, according to a filing from her attorney: “Mother had attended all eleven parenting times, had procured employment, was in therapy, lived in three-quarters housing, and tested negative for illegal drugs during the current reporting period.”

Then that July, Herrera’s saliva tested positive for cocaine. Herrera admitted to being in recovery from an addiction but denied using the drug. Over the next eight months, two more of her drug tests were confirmed positive for cocaine by the state’s lab. She sought testing from an outside lab, which didn’t detect illegal drug use.

According to her test results from the state’s lab, which Herrera shared with ProPublica, the levels of cocaine and its metabolite in her system ranged from 1.065 to 1.774 ng/ml, just above the state’s cutoff of 1 ng/ml in saliva. If the positive-test threshold for federal workers had been applied to Herrera’s tests, she could have had more than four times as much of the drug in her saliva and still been cleared to fly a plane.

But Herrera’s positive test from December 2019 caused the judge to take away her unsupervised parenting time, according to court records.

“The positive drug tests turned my world upside down and ruined my life,” said Herrera. What she didn’t know is that behind the scenes, Michigan’s child welfare agency was reviewing — and preparing to raise — its cutoff levels.

Michigan’s levels for cocaine and other drugs in saliva had been set by its drug testing vendor, Forensic Fluids, in 2018, according to public records. (Forensic Fluids did not respond to a request for comment.) Michigan contractually required the same levels when it signed with a new lab, Averhealth, in 2019. 

But the child welfare agency noticed conflicting results between its tests and those ordered by law enforcement agencies, according to public records. Some individuals who tested positive for a drug with one agency tested negative with another.

In November 2020, at the urging of its new lab, the agency raised its levels. Communications between the agency and Averhealth show both were concerned that low cutoffs might not be “forensically defensible” due to “uncertainty around environmental exposure.”

“Current levels … are scientifically unsupportable,” Michigan’s child welfare agency wrote in a memo about the change.

In a statement, Averhealth, the lab that processed Herrera’s tests, said the mismatch in results  that concerned Michigan administrators “in no way calls into question the accuracy or reliability” of its testing. “Inconsistencies occurred when different types of tests were conducted (saliva or hair) or when the individual was tested days later,” the company said, noting that “different types of testing have different limitations.” The company said its test results “simply attest to whether a drug is present in a specimen and, if so, in what quantity. It is left to the courts to decide what, if any consequences, follow.”

In Herrera’s case, the lab said, low-level cocaine positives “likely represent ingestion of cocaine” and that “passive exposure as an explanation is highly doubtful.” The company also pointed out that Herrera had several high-level positive tests for methamphetamine in the fall of 2020, nine months after the court took away her unsupervised parenting time. 

Herrera admits she’s relapsed at times. But she also says that being labeled a cocaine user early on in her case, when she says she wasn’t using, derailed her recovery. Herrera believes it set her up to fail by creating an adversarial relationship with her caseworker and judge. “I wasn’t grateful about what they were doing to me,” she says.

Herrera’s parental rights were terminated in 2021, less than a year after Michigan raised its cutoff levels for cocaine in saliva. In denying Herrera’s appeal, a judge cited her refusal to participate in further drug tests, additional failed tests when she did comply, and her lack of housing and income, among other things.

When Herrera was told she could never again see her kids, she said, she was devastated and relapsed again. “Fuck it, if they say I’m an addict, then I’ll numb the pain.”

“I think about my kids every single day,” she said. “It’s affected me completely.”

Even after raising its cutoffs, Michigan’s levels were still far lower than those used for federal workers. The state declined to comment, but a memo stated that officials considered the federal levels inappropriate because they “do not assess the impacts of how those substances may affect a person’s behavior” or “how that use may impact child safety.”

Drug testing policy experts say it’s not possible for any test, no matter the cutoff level, to reliably predict child safety.

“A drug test doesn’t tell you if a person has a substance use disorder, if they are in recovery, or whether a child is safe,” said Nancy K. Young, executive director of Children and Family Futures, which consults for child welfare agencies, and co-author of a Substance Abuse and Mental Health Services Administration policy paper on drug testing for child welfare agencies. Young said administrators should consider test results as “just one data point” and rely more on “casework and a relationship with the family” to determine whether a child is safe and well.