Codeine testing in sweat and saliva with the Drugwipe

Area of Science:

• Forensic Toxicology
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Growing demand for immediate, on-site drug testing.
• Introduction of the Drugwipe, a non-instrument-based immunodiagnostic assay for drug detection.
• Availability of Drugwipe tests for opiates, cocaine, and cannabis.

Purpose of the Study:

• To evaluate the Drugwipe "opiate" assay's performance on human biological fluids (sweat and saliva).
• To compare Drugwipe results with Gas Chromatography-Mass Spectrometry (GC/MS) reference standards.
• To document the practical applications and limitations of the Drugwipe for opiate detection.

Main Methods:

• Oral administration of codeine phosphate to six subjects.
• Sweat testing using Drugwipe on forehead at 1, 4, 9, and 24 hours post-administration.
• Simultaneous sweat patch application for reference quantification via GC/MS.
• Saliva testing using Drugwipe and saliva collection for GC/MS comparison over 24 hours.

Main Results:

• Drugwipe correctly identified opiates in sweat in most subjects, with some false negatives.
• Drugwipe detected codeine in saliva, but numerous false negatives were observed compared to GC/MS.
• Several cases showed positive GC/MS results for codeine in saliva where Drugwipe yielded negative results.

Conclusions:

• The Drugwipe "opiate" assay demonstrates potential for on-site sweat testing but requires further validation.
• The Drugwipe assay shows significant limitations for on-site saliva drug testing due to false negatives.
• Low codeine concentrations, interfering substances in saliva, or inadequate sampling may explain discrepancies.