Bethesda, MD: Saliva tests do not reliably detect the presence of THC, according to a review of ten separate oral fluid, point-of-collection drug testing devices published in the January/February issue of the Journal of Analytical Toxicology.
Researchers at The Walsh Group in Bethesda, Maryland, evaluated the reliability of ten oral fluid devices to detect various controlled substances, including THC and it's inactive metabolite THC-COOH, at cutoff concentrations recommended by the manufacturers.
Of the ten devices tested, six recorded either false negative or false positive test results for THC. Five devices also recorded false positive results for THC-COOH.
Manufacturers' proposed cutoff guidelines for THC varied widely from product to product, from 15ng/ml (lowest recommended cutoffs) to 600ng/ml (highest recommended cutoffs). Currently, no federal regulations govern oral fluid testing cutoff standards.
Investigators concluded, "The detection limits are improving for THC, but reliable detection of marijuana use in forensic investigations, such as driving under the influence and the workplace, remains problematic."
Previous evaluations of onsite oral fluid tests have also shown the technology to be unreliable for detecting the presence of cannabis, particularly when administered at roadside checkpoints. Several European nations and a handful of US states are testing the use of such devices in an on-going field study investigating the prevalence of motorists who drive under the influence of controlled substances.
For more information, please contact Paul Armentano, NORML Senior Policy Analyst, at (202) 483-5500. Full text of the study, "Evaluation of ten oral fluid point-of-collection drug-testing devices," appears in the January/February issue of the Journal of Analytical Toxicology.