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Papain: a novel urine adulterant
David L Burrows1, Andrea Nicolaides, Peter J Rice
1Section of Toxicology, Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, 37614, USA.
Journal of Analytical Toxicology
|August 18, 2005
Summary
Papain can interfere with drug screening tests by decreasing marijuana metabolite concentrations, potentially leading to false negatives. Immediate testing is recommended to mitigate papain
Area of Science:
- Forensic Toxicology
- Biochemistry
Background:
- Urine drug screening is common in the workplace, with marijuana as the most frequently detected illicit substance.
- Urine adulterants can interfere with drug tests, leading to false-negative results.
- Papain, a cysteine protease, has ester hydrolysis capabilities that may affect drug metabolite stability.
Purpose of the Study:
- To investigate the potential of papain as a urine adulterant to interfere with drug screening.
- To determine if papain affects the detection of THC-COOH (marijuana metabolite) and other common drugs.
- To assess if papain adulteration invalidates urine specimens according to proposed SAMHSA guidelines.
Main Methods:
- Analyzed THC-COOH concentrations using Fluorescence Polarization Immunoassay (FPIA) under various pH, temperature, and papain concentrations.
- Tested other drugs (amphetamines, barbiturates, etc.) using FPIA, and THC-COOH/nordiazepam using GC-MS/HPLC-UV.
- Assayed urine specimens for creatinine, specific gravity, and pH to evaluate specimen validity.
Main Results:
- Papain significantly decreased THC-COOH concentration in a pH, temperature, and time-dependent manner (up to 50% decrease in 72 hours).
- Papain caused a 66% decrease in THC-COOH and a 24% decrease in nordiazepam concentrations.
- No specimens adulterated with papain were invalidated based on proposed SAMHSA guidelines.
Conclusions:
- Papain acts as a urine adulterant, specifically interfering with the detection of THC-COOH and, to a lesser extent, nordiazepam.
- Immediate drug screening is advised to minimize papain's interference with primary immunoassay methods.
- Papain adulteration does not appear to invalidate specimens based on current proposed validity testing guidelines.