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Science Revisited: Will Using CBD Hemp Oil Lead to a Positive Drug Test for THC?

This article is sponsored by PlusCBD Oil, a product line from CV Sciences (formerly CannaVest). CV Sciences is one of the leading suppliers and manufacturers of agricultural hemp-derived CBD bulk and finished products.

Disclaimer: The information provided in this column is intended for educational and informational purposes only. CV Sciences is not engaged in rendering legal or medical advice, and any information provided is not a substitute for professional legal or medical opinion.

You may recall part one of our now two-part series that explores whether a person using CBD hemp oil could test positively for THC or marijuana. The study cited concluded the following:

“…a consumer who uses a high-quality, scientifically vetted hemp-based product at the standard serving size is highly unlikely to test positive for THC and/or THC-COOH. However, it’s important to be cognizant that extremely high doses may result in a positive urine screen (that would be subsequently shown to be false via GC/MS). “

An additional study conducted by Leson, et al dove further into the subject, examining the effects of THC administration on subjects who had positive drug screens for THC. What were their findings, and do they align with Part 1’s findings or contradict the initial study’s results?


The Latest Study

Research lab equipment

Leson and colleagues’ recent study involved 15 adult subjects (10 females, 5 males) who had not previously been exposed to THC. The subjects were given single daily THC doses in an oil matrix, ranging from 0.09 to 0.6 mg, over four successive 10-day periods. Their urine samples were screened for cannabinoids using radioimmunoassay, a method of measuring very small amounts of a substance in blood.

Unfortunately, radioimmunoassay is prone to producing false positives, and it confirmed the presence of THC-COOH. The radioimmunoassay results showed that daily ingestion of up to 0.45 mg of THC in an oil matrix did not screen positive at a 50 ng/mL cutoff. When the daily intake was increased to 0.6 mg, one sample screened “positive”. At the lower cutoff level of 15 ng/mL (which is used by some employers, law enforcement agencies, and drug treatment programs), 19% of urine samples screened “positive” for THC.

However, when the samples were analyzed using gas chromatography-mass spectrometry (GC-MS), an analytical method of identifying different substances within a test sample, none of the samples screened positive. In fact, under the GC-MS method, the highest value obtained was only 5.2 ng/mL, well below the lower cutoff level of 15 ng/mL.

The researchers concluded the following:

“Practicing routine GC-MS confirmation of urine specimens screening positive appear to minimize the risk of producing confirmed positive urine tests from hemp oil.”

So there you have it. If you keep your consumption of CBD-rich hemp oil to less than 200 to 300 mg per day, you are highly unlikely to screen positive for THC use via the confirmatory (and most important) GC-MS test. Therefore, less than 100 mg to 150 mg daily is very unlikely to result in a positive preliminary immunoassay-screening test.


But Wait, There’s More

Cannabis CBD oil poured onto white table with small container of oil and cannabis flower placed nearby

One caveat is that CBD, THC, and other cannabinoids are known to interact with a subclass of a very important family of enzymes known as the cytochrome P450 group (abbreviated as CYP). CBD is known to inhibit the same P450 enzymes that are known to metabolize it, and some of these enzymes (e.g., CYP3A4 and CYP2C9) are also responsible for THC metabolism along with the hepatic metabolism of ~ 60% of clinically prescribed medications. Co-administering cannabis and CBD may cause THC levels to be elevated to a greater extent, for a prolonged period of time.

Medical marijuana patients who utilize high doses of CBD concentrates should keep in mind that there are multiple potential drug interactions. Moreover, there is also the issue of pharmacogenetics– the degree of variability with which an individual’s genetics causes differences in drug metabolic pathways, which can affect how someone responds to the therapeutic benefits as well as adverse effects of drugs. Hence, the actual dose that causes a potential “positive” screen or confirmatory test for THC from consumption of CBD-rich hemp oil will change from one individual to another due to these genetic differences in the CYP450 enzyme system.

Does Using CBD Hemp Oil Result in a Positive Drug Test for THC or Marijuana?

New References:

Bergamaschi et al. Safety and Side Effects of Cannabidiol, a Cannabis sativa Constituent. Current Drug Safety, 2011, Vol. 6, No. 4.

Leson et al. Evaluating the impact of hemp food consumption on workplace drug tests. Journal of Analytical Toxicology, Vol. 25, November/December 2001 691-698.

  • Carmen Kelp

    Well that was not very clear. I’m going to buy a urine test on amazon and test myself. I take Sundance Cosmetics 50mg hemp cbd drops at night and and also vape a little during the day. I also use the topical hemp cream and/or hemp massage oil as needed for pain. I will post the results here next week so stay tuned!

    • Audrey Walker

      Carmen, please share your results

      • in my experience, the topicals do not test positive, however the oral tinctures do if there is ANY thc in them.

  • Is good to search and find good reviews about Cannabidoil & other Marijuana components lab testing. #SClabs is who we use, but lately i have had mixed feeling so i did my own research so i wanted to make sure others know that testing with a good lab is very important & we recommend #CBDEdibles #CBDcandy #CBDSweets #CBDLabs #CBDTesting

  • L.Harts

    I am a chronic pain patient w/Fibromyalgia & a host of other problems. I take large doses of opioids. I would like to try CBD to see if I could get off or significantly reduce the amount of opioids. The problem is > My Dr’s are in a Pain Clinic, They do urine tests every few mo’s. I don’t know if they test for THC I just can’t take a chance. My family has been trying to get me to try edibles/medical Canibus for years, but I am too worried to even drink alcohol let alone try anything. But to my suprise 2mo. ago Out of the Blue ,(after a mouth swab) I tested positive for Cocaine. Lowest trace amount detectable.
    IT WAS A BAD TEST! . & Nothing I can do about it. Forever now my medical records will show a positive.
    This makes me Even MORE intrested in getting away from the opioids, & the pain clinics. I do not use recreational drugs, with all the medication I am on it would just be Crazy & That I Am Not!!
    `+So U have my background, Do You Think The CBD would show up on a urine test? Or that my other medications could mix w/it and give a strange reading? I’d Really Appreciate your help! Thanks L.Harts
    — ——————————–

    • Diane Santa Cruz

      This is also why I looked at this thread. I get negative opioid test results though. Test says I am not taking my pills. I’ve failed 3 of them, but never miss a pill. I do not take anything my doc has not prescribed me at all, ever. It’s BS being treated like a drug dealer when I’m as pure as the driven snow. They need to get more accurate tests. That said, I was desperate the other night after driving 6 days straight and had my husband apply a bit of CBD cream on my lower spine. Such fast relief! It was amazing. However, now I’m afraid I’ll pop positive when I go in on the 22nd. He also applied it on his knee and felt the same quick result.

      • coreyp

        What brand cbd cream.

        • the one I use is 100 mg full spectrum hemp and it does work

      • White Prowler

        F it. Just do the CBD and f what a doctor thinks.

    • White Prowler

      There is cocaine on cash sometimes. You could gave handled some cash and tested positive for cocaine because of that.

      • Jayste

        He had a mouth swab. I tested positive for cocaine once at pain management, but when they sent it off it came back negative.

  • LynnLynn

    I only take CBD oil for chronic pain. It’s working great for that. However, it seems impossible to get a straight answer on this so I decided to test myself and share the results. Unfortunately, I tested positive using an easy@Home test. Did 2 tests a few days apart. Both showed positive for THC. CBD is legal in my state. Medical marijuana isn’t.

  • Will Patterson

    CBD oil will show up on a mouth swab. I was called in for the drug test 5 days after using it. Tested positive for THC and lost my job. Even though it helped my pain, I will never use it again.