Ask the experts: Secondhand marijuana smoke

Q:  Can secondhand marijuana smoke render a positive drug test?         

There are many ways to use marijuana; smoking the drug using a pipe or as a rolled cigarette or joint likely remains the most popular method. This method of consumption, much like tobacco cigarettes, produces smoke which can be indirectly inhaled by non-users. The Centers for Disease Control and Prevention (CDC) states that this secondhand marijuana smoke does contain delta-9-tetrahydrocannabinol (THC), the psychoactive chemical in the cannabis plant that produces its “high.” Understanding the effects secondhand marijuana smoke can have on a drug test is a common question received by our teams of scientists.

We asked Dr. Barry Sample, Senior Director of Science & Technology at Quest Diagnostics, to share his expertise in an effort to clear the air on this topic. He said, “There are no published, peer-reviewed studies to date that indicate, even with today’s increased concentrations of THC in marijuana, that someone would test positive due to ‘passive’ or ‘incidental’ exposure at events such as parties or concerts.” The National Institute on Drug Abuse (NIDA) concurs, reporting that it unlikely that secondhand marijuana smoke could give someone a contact high after examining research that measured factors such as drug potency, hours of exposure, and room ventilation.

Quest Diagnostics offers testing for marijuana using urine, oral fluid, and hair specimens. New oral fluid testing technology has proven effective in detecting recent marijuana use. When compared to urine, oral fluid demonstrates higher positivity rates for almost all drugs and more than twice the positivity rates for marijuana. It’s important to select a test type and cutoff that will effectively screen for the drug.

For more information about drug testing, visit our website or contact us online.

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