The inadequacy of current forensic thresholds in child protection cases

Children may be exposed to illicit substances through passive environmental exposure, accidental ingestion, or intentional administration, often in the setting of caregiver drug use. We present a case series of children younger than 12 years of age who were referred to our toxicology center by judicial or child-protection authorities between January 1, 2023, and January 31, 2026. Urine and hair specimens were analyzed with validated liquid chromatography-tandem mass spectrometry. Cases attributable to medically administered or legally prescribed substances and one fatal case were excluded. Among 54 children with confirmed positive findings, 30 were male, and the median age was 2.6 years. Known caregiver drug use was the most common indication for testing (66.7%), and most children (87.0%) were asymptomatic. Methamphetamine was the most frequently detected urinary substance (35 children [64.8%]; median concentration, 20.7 ng per milliliter; interquartile range, 11.1 to 69.6), and most median urinary concentrations were below applicable statutory confirmatory cutoffs. Six children underwent both urine and hair testing. Hair testing identified additional or more remote exposures, including N,N-Dimethylamphetamine, ketamine, and norketamine. These findings suggest that adult-derived forensic thresholds and urine testing alone may miss pediatric drug exposures that are clinically relevant to child protection.