2025 Medical Review Officer Online Course with Live Discussion (Includes Digital Syllabus)-Tab 7: Forensic Laboratory Urine Testing

Tab 7: Forensic Laboratory Urine Testing

Pdf Summary

The document outlines comprehensive considerations and procedures for forensic urine drug testing laboratories, focusing on legal defensibility, accuracy, and specimen validity. The primary goals include reliably distinguishing specimens above or below cut-off drug/metabolite concentrations, identifying adulteration or substitution, and ensuring proper chain of custody throughout collection, receipt, screening, confirmation, and reporting stages.<br /><br />Initial drug testing employs FDA-approved immunoassays or alternative technologies like LC/MS/MS to screen specimens. Negative specimens have drug/metabolite concentrations below established cut-offs, while positives meet or exceed these thresholds. The cut-offs, such as 50 ng/mL for marijuana metabolites and 150 ng/mL for cocaine metabolites, are regulated by entities like HHS and DOT, ensuring standardized discrimination.<br /><br />Confirmatory testing, performed on a separate aliquot, uses chromatographic and mass spectrometry methods (e.g., GC/MS, LC/MS/MS) offering greater specificity to definitively identify drugs/metabolites at regulatory cut-offs. Laboratories must validate all testing methods and maintain robust internal and external quality control (QC/QA), including blind performance testing and periodic audits.<br /><br />The document details updated methamphetamine reporting—positivity requires ≥250 ng/mL methamphetamine; amphetamine presence is no longer mandatory. It also highlights drugs not currently included in HHS standard panels, such as synthetic cannabinoids ("K2/Spice"), synthetic stimulants ("bath salts"), various fentanyl analogs, and designer benzodiazepines like bromazolam.<br /><br />Specimen validity testing assesses whether urine is consistent with human physiology, detecting dilution, substitution, or adulteration. It involves measuring creatinine, specific gravity, pH, nitrite, and presence of adulterants (e.g., chromate, glutaraldehyde). Criteria define specimens as substituted, diluted, adulterated, invalid, or negative based on these parameters. DOT regulations specify immediate recollection protocols for dilute results. Laboratories must retest split specimens and maintain rigorous chain of custody.<br /><br />The document concludes with sample self-assessment questions for Medical Review Officers (MROs) on drug testing cut-offs, metabolism, specimen validity, and reporting nuances, underscoring the complexity and regulatory framework guiding forensic drug testing laboratories.

Keywords

forensic urine drug testing

specimen validity

chain of custody

immunoassay screening

LC/MS/MS confirmation

cut-off concentrations

quality control

methamphetamine reporting

synthetic cannabinoids

Medical Review Officers