Confirmatory GC–MS Drug Testing in Pediatric Patients: A Clinical Case Series Highlighting False-Positive Results and Child Protection Implications

Drug exposure in pediatric patients represents a major clinical and forensic challenge, particularly when initial urine drug screening relies on immunoassays with limited specificity. False-positive and false-negative results may lead to inappropriate clinical decisions or delayed child protection interventions. We conducted a retrospective case series of 14 pediatric patients (0-5 years) with suspected drug exposure evaluated in a hospital emergency setting. Positive immunoassay urine drug screens were submitted for confirmatory analysis using gas chromatography-mass spectrometry (GC-MS) at a reference toxicology laboratory. GC-MS confirmation identified a wide range of illicit and prescription substances and metabolites, including benzoylecgonine, cocaine, ecgonine methyl ester, phenobarbital, para-hydroxy-phenobarbital, lorazepam, morphine, sertraline and its metabolites, hydroxymidazolam, MDMA, MDA, and 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH). In several cases, GC-MS resolved discordant screening results by identifying immunoassay false positives caused by cross-reactivity or by detecting substances missed during initial screening. Confirmatory GC-MS testing directly influenced clinical management and supported child protection decisions in cases of suspected neglect, accidental ingestion, or environmental exposure. These findings reinforce the critical role of mass spectrometry-based confirmation in pediatric toxicology to ensure diagnostic accuracy and appropriate clinical and legal outcomes.