02-04-19 Does CBD oil cause a false positive for THC on UDS?

Toxicology Question of the Week

February 4, 2019

Does CBD oil cause a false positive for THC on UDS?

I was asked the above question by a health care provider.  I immediately sent it to the expert, Jennifer Colby PhD, Chief of the analytic tox lab.  This is what she said:

CBD oil presents a interesting issue.  If the CDB oil was legally acquired in TN it should have a max THC content of 0.3%.  If it was acquired elsewhere (or if it came from a manufacturer overseas with poor quality control) all bets are off.  If a patient is using locally sourced oil from a reputable manufacturer, I would be surprised if the low-level contamination was enough to cause a positive screen.  As far as I know there are no regulations about the concentration of cannabinol in the CBD oil, so it could be there are relatively high amounts, enough to cause a positive screen.  However, I have not tested that, and I am not aware that anyone else has. 

Question prepared by Jennifer Colby PhD, Associate Director of Clinical Chemistry, VUMC

I am interested in any questions you would like answered in the Question of the Week.  Please email me with any suggestion at donna.seger@vanderbilt.edu

Donna Seger, MD

Executive Director

Tennessee Poison Center


Poison Help Hotline: 1-800-222-1222

The Question of the Week is available on our website: www.tnpoisoncenter.org