Identifying Marijuana Use
Marijuana, also known as cannabis, is a plant material obtained from cannabis sativa. It is used as medication or recreational purposes. Although the Cannabis plant contains hundreds of compounds, delta-9-tetrahydrocannabinol (Δ9-THC or THC) is psychoactive and produces several pharmacological effects. Hashish is the product created from the resin of marijuana flowers. Hash oil or cannabis oil is an oleoresin extracted from cannabis or hashish.
Prevalence of marijuana use
Federal and state law for marijuana use
Marijuana use disorder
1) Presumptive Drug Testing
The most common screening methods used to detect marijuana/cannabinoid in urine is by enzyme immunoassay (EIA). THCCOOH is usually detected by EIA; however, due to cross-reactivity, other cannabinoids present in the urine may also be reactive with the marijuana/ cannabinoid EIA. Therefore, immunoassay results are expressed in terms of "total cannabinoids" and not specifically in terms of THCCOOH concentration. The cut off or threshold reporting limit for detection of cannabinoids used by the US Substance Abuse and Mental Health Services Administration (SAMHSA) is 50 ng/mL.
2) Definitive Drug Testing
Gas chromatography–mass spectrometry (GC-MS) or Liquid Chromatography with tandem mass spectrometry (LC-MS-MS) can be used for identification confirmation as one use of definitive drug testing. The specimen type and advantages and/or disadvantages are shown in the table below (Table 1).
Table 1.Confirmation Testing of Marijuana from different specimen type.
A Lawsuit Waiting to Happen: Get Cannabis Testing Right or You Will End Up in Court!
Legal cannabis and hemp or CBD has become the latest rave racing rapidly across the U.S.and finding its way into many consumer products. The availability of products containing CBD in varying proportions is increasing exponentially.As CBD products surge in the marketplace they also present employers who conduct drug testing with a new issue, Can Common Drug Test Used by Employers Tell the Difference between CBD or THC?
CBD oil is short for cannabidiol and is a compound found in cannabis. CBD, a non-intoxicating compound that, like Tetrahydrocannabinol, or THC, is found in varying amounts in the plant known as cannabis.
“THC, is the chemical compound responsible for marijuana’s euphoria and is usually screened for in a typical urine drug test. When drug testing is mandated, employers follow guidelines, such as the Substance Abuse and Mental Health Services Administration (SAMHSA), which has a set cutoff level for a positive test at > 50 ng/mL. When a test is positive, it then gets screened again with a confirmatory GC/MS or LC/MS test, which have cutoff levels of 15 ng/mL and is specific only to the THC metabolite.” 1
THC is federally illegal, however, in December 2018the U.S. Farm Bill legalized hemp — cannabis that contains less than 0.3 percent THC. With that, CBD became legal. It can now be found at stores across the country, in everything from massage oils, sleep aids, coffee, cookies, gummy bears, make-up, etc.
Although most CBD products claim to have under 0.3% THC, which is classified as hemp, the products remain unregulated making the THC levels unreliable.
Amy Norton of Health Day Reporter wrote in her article. ‘Pure CBD Won’t Make You Fail a Drug Test. But . . .’, “a preliminary studyled by Grace Kroner, lead researcher, of the study conducted by the University of Utah Health Sciences Center in Salt Lake suggests thatCBD won’t make you fail a drug test — at least if the CBD is pure.Researchers found that CBD, or cannabidiol, did not react with either of two commercially available tests used to screen for marijuana use. However, another cannabis compound — cannabinol (CBN) — did.”
While the above study’s information is informative it is important to note that according to a recent article, ‘Will CBD Oil Result in a Positive Drug Test?’ by DISA, a provider of workplace safety and compliance services, the DEA states, “for practical purposes, all extracts that contain CBD will also contain at least small amounts of other cannabinoids. Although it might be theoretically possible to produce a CBD extract that contains absolutely no amounts of other cannabinoids, the DEA is not aware of any industrially-utilized methods that have achieved this result.”
The Problem: Can Common Drug Test Used by Employers Tell the Difference Between CBD and THC?
Drug tests for marijuana detect THC, not CBD, which means even hemp-based CBD products can have low amounts of THC. Drug tests do not determine the type of substance an employee took, only if it contains THC.
“A little-known study published in 2012 in the Journal of Analytical Toxicology that showed that a common forensic drug testing method could easily mistake the presence of CBD for THC. According to the 2012 journal article, trifluoroacetic anhydride, or TFAAwhen used by a GC-MS machine was unable to discern between CBD and THC. If a person who used only CBD were given a drug test that employed this device, method and chemical, the results would falsely report the presence of THC.
Bruce Houlihan, director of the Orange County, Calif., crime lab and chair of the emerging drugs and opioids committee for the American Society of Crime Lab Directors, noted that many labs have upgraded from GC-MS analysis to a more precise technique called high-performance liquid chromatography. However, Mr. Houlihan added,” tests using GC-MS are still common and many of those may be using TFAA.”
In addition, two chemists with Cascade Chemistry, a private chemical-research company in Eugene, Oregon, independently reviewed the study for The New York Times and confirmed the validity of the potential drug testing problem.
Frank Conrad, the chief technology officer and lab director at Colorado Green Lab, a scientific consultant to the cannabis industry, said,“I can’t even estimate how many people this is going to screw over.”
Houlihan expressed concern, saying that “If any labs are using this method, they’ll have to be careful.” He added that there was no way to estimate how many drug testing labs might be accidentally mistaking CBD for THC, because forensic labs generally determine their methodology in house.
It is also difficult to estimate how many people in a year have suffered negative consequences, such as the loss of a job or parental rights, after testing positive for THC, because most drug testing data is private.
Nonetheless, a drug test that identifies THC that was acquired through legal CBD products could have serious consequences for the individual because even in states that have legalized marijuana, it remains legal for employers, to test for THC.
For example, a woman who was fired from her job last year following a urine drug test from Quest Diagnostics has claimed that a CBD product caused her to test positive for THC.
The woman had been taking the CBD product for a few weeks when she went in for a scheduled drug test. The company that produced the product is based in Colorado and appeared to be legitimate, she said, so she was shocked when she failed the drug test. “They were reputable,” she said. “They had their lab results on their website.”
Barry Sample, the senior director of science and technology at Quest Diagnostics said that unreliable identification of THC levels in the products used was most likely the problem and likely why her Quest drug test showed that she had used THC. But the woman insisted that the CBD product she purchased did not get her high and did not have any THC.
False positives in drug tests are just one of many issues that have arisen as drug testing firms and law enforcement authorities attempt to catch up with the rapidly shifting laws around the cannabis industry.” 2
What Should Employers Do?
Drug Testing Methodologies
The first option employers should consider is to engage with their drug testing firm to ensure they are appropriately addressing this issue by using the most recent testing processes and procedures to minimize false positives.This could include expanded drug panels and multiple testing methodologies to enhance their drug testing program.
This is also an excellent time to take advantage of the expertise of your drug testing firm to help you determine the best approaches you should consider to address this issue.
A recent Gallup Survey reported that an estimated 14% of Americans are using these products which likely includes some of your employees. With this rapid growth in the use of products containing CBDanother avenue for employers to consider isto educatetheir employees about CBD and THC. Employees need to be aware that CBD is not regulated and identified levels of THC in products are not reliable.It benefits employers for their employees to be able to make an informed decision and to fully understand that despite using these products legally they may inadvertently result in a positive drug test. As the saying states, “forewarned is forearmed.”
“Reinforcing this point is a study conducted by Ryan Vandrey, Ph.D., associate professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine. The studyfound that individuals who are subject to urine drug testing should understand that even very small amounts of THC in a CBD/hemp product can trigger a positive result for cannabis. They should know that conventional drug tests cannot distinguish whether THC present in someone’s system came from cannabis, or a federally-legal hemp product.”
The Johns Hopkins study also highlighted the issue of some poorly regulated CBD products being advertised as “THC free,” that actually contain levels of THC similar to (or higher) than the THC levels present in the cannabis used in a study conducted by Ryan Vandrey, Ph.D.
This information is especially important for people who use hemp/CBD products daily for therapeutic reasons, to know that, THC can potentially build up in a person’s system with repeated use, which could further increase the chances of a positive result for cannabis.” 3
Vandrey and his collaborators at the University of Pennsylvania published a JAMA study showing that that 21% of CBD/hemp products sold on the Internet contained THC, even though their labels didn’t properly disclose it.
This may also be a good time for employers to take a step back and revisit their marijuana related drug testing policies and procedures to see it they are in tune with the times and the rapidly changing legal marijuana use picture across the country.
This could include implementing Medical disclosure policiesso that employees working in a safety-sensitive position disclose their prescription drug use to the employer, helping to cover all bases for legal drug use that ‘zero tolerance’ policies don’t provide.
Additional options includeestablishing a protocol to address THC positive results which could involve
- engaging in an interactive process and accommodation analysis if the employee has a prescription to use medical marijuana to determine if there should be an accommodation (be sure to check your state laws on this.) A critical question to answer here is ‘does the employee’s use of medical marijuana off-duty impair the person or interfere with their ability to perform their job or create an unacceptable safety risk?’
- implementingenhancedpre-Adverse Action processes which provide the person the opportunity to explain the CBD products they have used and to producedata that supports their legal use and
One of the main issues employers should understand is the fact that many hemp or CBD products, regardless of their legality in a state, are unregulated and can contain THC which might show up on a drug test. CBD products’ identification of THC levels are not reliable, consequently, employees using the suggested serving size might test positive on a drug test even if they are legally using the product and using the recommended doses.
It is important for employers to understand that workforce drug test commonly used are designed to identify the presence of THC, however, they cannot identify whether the source of the THC is marijuana or CBD. Consequently, employers should understand while it’s improbable that an employee using hemp-derived CBD products will test positive since the person would have to consume above 1000-2000mg of the product, considered a relatively large amount.However, it is not impossible and could still happen.For this reason, employers need to anticipate the possibility of situations arising in which employees have legally and appropriately used CBD products receiving a positive test for THC.
A very critical point of this article is to let employers know that its’ important to increase their knowledge about CBD and THC so they do not automatically jump to the conclusion that a positive test by an employee for THC warrants termination. The landscape for drug testing of marijuana is evolving and employers approaches to dealing with this issue needs to evolve as well or they can wait and let the courts decide.
- Will CBD Oil Result in Positive Drug Test?, DISA, https://disa.com/blog/will-cbd-oil-result-in-a-positive-drug-test, July 22, 2019.
- Lewis, Amanda Chicago, CBD or THC? Common Drug Test Can’t Tell the Difference, 15, 2019.
- Hasse, Javier, ‘Legal CBD Products May Make You Positive ForCannibis in Urine Drug Tests, John Hopkins Study Says,’ November 6, 2019.
About the Author
Barry Nixon is the COO, PreemploymentDirectory.com the leading background screening information portal and online worldwide directory of professional background screening firms and Suppliers to the background screening industry. He co-authored the landmark book, Background Screening & Investigations: Managing Hiring Risk from the HR and Security Perspective. He also is the publisher of award winning newsletters, The Background Buzz and The Global Background Screener, and the author of the Backgrounder column in PI Magazine.
In addition, Barry is a past recipient of the elite ‘Top 25 Influential People in Security’ by Security Magazine and past Co-Chair, International Committee for the Professional Background Screening Association (PBSA). He also served as a Global Ambassador for PBSA for many years.
Scenario: Finding THC in Test Results for a Patient on Opioids and NSAIDs
A 52-year-old male with chronic cervical radiculopathy, back pain, and knee pain presents to his physical medicine and rehabilitation (PM&R) clinic for a regularly scheduled appointment. His pain has persisted since involvement in a serious car accident 3 years prior. As part of his agreement with the clinic, the patient undergoes annual urine drug monitoring. The patient’s pain medication regimen consists of:
- hydrocodone/acetaminophen, 10 mg/325 mg every 6 hours as needed for back and knee pain
- ibuprofen, 600 mg every 6 hours as needed for radiculopathy
- a lidocaine 5% patch, once daily for back pain
After further discussion, the patient admits to taking cannabidiol (CBD) oil because it “really seems to help his knee pain” and he “knows he can’t get high on it.”
Patient Use of Marijuana or Cannabidiol
Many patients may want help with a medical or psychological problem they are experiencing but may not wish to take more medications; they may lean toward finding a “natural” remedy without fully understanding its safety profile or risk. CBD products and, depending on the state, marijuana may be easier to access for these patients than a visit to their prescriber and pharmacy.
Marijuana contains multiple cannabinoids, one of the most well-known being the psychoactive component, tetrahydrocannabinol (THC). 1 Some individuals utilize marijuana specifically for its psychoactive properties while others use it because they find it helps with various afflictions. Some individuals claim both recreational and medical use of marijuana. Based on survey data from approximately 170,000 US adults that use marijuana, individuals with documented medical conditions were more likely to use marijuana than those without a medical condition. 2
CBD is another cannabinoid that comes from the cannabis plant but it does not have psychoactive properties or produce psychoactive metabolites. 3 CBD vendors may boast the substance’s ability to treat anxiety, sleep disorders, nausea, seizures, and pain, among other conditions. Only one CBD product, Epidiolex, has an FDA-approved indication for treatment of seizures associated with Lennox-Gastaut syndrome or Dravet syndrome. 4
Drug Monitoring for Tetrahydrocannabinol (THC, marijuana)
Urine drug monitoring is one of the most frequently utilized methods to screen for use of THC and other substances. 5 These tests commonly detect the 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid metabolite of THC but may detect other metabolites as well. 5 Detection of THC in the urine is contingent on the frequency and duration of use, hydration status when the urine is collected, the quality of the substance used, and the individual’s fat content (THC is fat soluble and stored in adipose tissue). 5 Table I shows the duration of detectability in urine after use. THC may also be detectable in oral fluid (which typically tests for parent THC, not metabolite), blood, and hair with hair samples providing the longest window of detection. 5
Data based on Reference 5.
Note that passive inhalation of marijuana rarely causes THC accumulation of 50 ng/mL to trigger positive results on urine drug tests, especially in a setting where the individual is not within a confined space. 5,6
Drug Monitoring for Cannabidiol (CBD)
CBD products, on the other hand, should never result in a positive THC screening because CBD is not metabolized into THC. 3 Federal law states that, in order for CBD products to be utilized legally, they must have no more than 0.3% THC by dry weight. 7 However, manufacturing of CBD products is not regulated, and consumers run the risk of using a product with more than 0.3% THC present.
Bonn-Miller, et al. utilized liquid chromatography (LC) to investigate the THC content of 83 CBD extract products sold online. 8 The researchers discovered that 21% of these products contained THC with a varying concentration of 0 to 6.43 mg/mL. The latter amount is more than double the federal limit to be considered CBD. THC content beyond that of which is on the label of the product may occur for several reasons. For instance, activation of THC-producing genes may occur as a result of reproduction between a male and a female hemp plant. 9 Farmers wishing to keep their products federally compliant typically only grow female hemp plants. 9 Another possible culprit is a poor CBD extraction process that leaves behind unwanted THC. 9
Importance and Frequency of Drug Monitoring
There are no guidelines that address frequency of drug monitoring specifically for THC or CBD products. The US Centers for Disease Control and Prevention (CDC) have, however, released guidelines for prescribing opioids for patients with chronic pain, as in the patient case presented above. These guidelines encompass drug testing and recommend obtaining a baseline urine drug test followed by, at a minimum, annual testing as a universal risk-management strategy and effort to maintain patient safety. 10 Consensus recommendations from Argoff et al also suggest annual urine drug monitoring for patients prescribed opioids for chronic pain with a low risk of opioid misuse. Additionally, the authors suggest testing at least twice annually for patients at moderate risk, and at least 3 times annually for high risk patients. Further, urine drug monitoring should be performed as clinically necessary. 11 (Watch a related video on why clinical drug monitoring is important.)
Some prescribers may conduct more frequent testing to confirm that patients are taking their medications as prescribed and that they are only taking those medications. The most recent Quest Diagnostics Health Trends report found that 51% of Quest drug monitoring test results showed evidence of potential misuse of prescription medications. 12
Drug monitoring is also imperative for assessment of medication compliance, remission, and relapse in patients undergoing substance abuse treatment. 13 According to the US Substance Abuse and Mental Health Services Administration (SAMHSA), those undergoing opioid abuse treatment must receive at least 8 drug tests per year. 13 The true frequency of testing should be based upon a patient’s success in treatment. Some patients may require testing several times weekly to maintain sobriety whereas others may do well with monthly testing. Additionally, certain states may require more frequent testing than SAMHSA. 13 Drug monitoring of patients receiving psychological treatment for a diagnosed mental illness is not common practice; it may become prudent should a patient present with mood or behavioral changes. 5 Testing in this situation may help behavioral health practitioners exclude substance use as a potential contributing factor to their patients’ psychiatric symptoms. (See also, our case scenario on drug monitoring in patients undergoing medication-assisted treatment.)
What Tests are Available?
Both presumptive (also known as preliminary or qualitative) and definitive (also known as confirmatory) testing are available for THC but not for CBD. You can view Quest’s test code directory, for example, at: www.questdrugmonitoring.com/ test-code-directory#. See the 2 main types of urine drug monitoring tests. Table II shows some commonly available laboratory cannabinoid tests.
P indicates presumptive; D indicates definitive; M indicates medMATCH service offered by Quest – reports indicate whether the prescribed drug(s), as specified by the ordering provider, or other drugs are detected in a specimen; LC indicates liquid chromatography; IA indicates immunoassay; MS indicates mass spectrometry; GC indicates gas chromatography. Data based on Reference 14 and communication with a Quest Diagnostics representative via phone on 01/21/2020.
Interpretation and Discussion of Drug Monitoring Results
In any setting, it is important for the provider to explain why a patient is being tested, how the provider will use the results, and that the results are confidential despite what they may show. 5 Patients are likely to benefit from a thorough, yet simple, explanation of their results including why a test was positive or negative, and what the results may mean in terms of their treatment plan. 5 (See a related video on how to discuss drug monitoring results with a patient.)
Expectations regarding findings of illicit substances or nonprescribed medications should be introduced during a patient’s first visit, before prescribing, and be presented in a nonjudgmental manner. For example, if a patient is being treated for a substance use disorder, a provider may explain that unexpected monitoring results could signal that a change in treatment is necessary. If urine drug monitoring frequently shows the presence of illicit or nonprescribed opioid substances, a referral for substance abuse treatment and/or a discontinuation of opioid therapy may be necessary. Providers are encouraged to use a Patient Agreement when prescribing opioids and controlled substances (see examples).
Returning to the patient case, the preliminary urine drug test yielded the results shown in Table III.
Fifty (50) ng/mL is the Quest Diagnostics’ laboratory cutoff for a preliminary positive result for THC. 14 If an individual tests positive for THC, the clinician should initiate a conversation with the patient to see if they can explain the test result. During this conversation, it is important to ask the patient about any prescription and nonprescription substances, vitamins, and supplements they may be taking. The case patient presented here has already endorsed utilization of CBD oil, which means THC contamination may be possible. However, it is also important to note other potential reasons for the positive THC result.
There have been reports of positive THC metabolite results on immunoassay with nonsteroidal anti-inflammatory drugs (NSAIDS), efavirenz, proton pump inhibitors (PPIs, such as pantoprazole), and hemp-seed food products. 6,15 Dronabinol, for instance, a cannabinoid indicated in adults for the treatment of: anorexia associated with weight loss in patients with AIDS, and for nausea and vomiting associated with cancer chemotherapy in patients who have failed to respond adequately to conventional antiemetic treatment,is likely to produce positive results on THC immunoassays because this medication consists of synthetic delta-9-tetrahydrocannabinol. 16 A true positive result may come as a surprise to a patient using only CBD as it may be assumed to contain less than 0.3% THC. Lastly, the patient may simply be utilizing marijuana or THC products.
Use of THC may or may not be permitted in a provider’s practice. In addition to the presumptive testing conducted, a provider may choose to proceed with definitive (quantitative) testing to determine the true cause of the positive THC result. Quest is developing testing methods for CBD. Providers can always reach out to the lab for assistance in ordering or interpreting testing or results.
- With the explosive growth in THC and CBD use both medicinally and recreationally, as well as evidence suggesting that legalizing marijuana might contribute to a modest reduction in opioid use, clinicians need to familiarize themselves with cannabinoid pharmacology, adverse effects, and monitoring strategies.
- CBD products may produce positive results on urine drug monitoring tests if the product contains more than the federally legal amount of THC as these products are not regulated by the FDA.
- A thorough patient interview and review of concomitant medications can help providers identify potential causes of urine drug tests positive for THC.
- Expectations regarding findings of illicit substances or nonprescribed medications should be discussed during the patient’s first visit with their provider.
Written by Courtney Kominek, PharmD, BCPS, CPE and Nicole Burns, PharmD. Disclosure: The case presented herein is hypothetical and the views presented do not represent those of the authors’ employers, the VA, or any federal agency.
1. CDC. What is Marijuana? Available at: www.cdc.gov/marijuana/faqs/what-is-marijuana.html. Updated 03/07/2018. Accessed January 17, 2020.
2. Dai H, Richter KP. A national survey of marijuana use among US adults with medical conditions, 2016-2017. JAMA Network Open. 2019;2(9):e1911936.
3. Ujváry I, Hanuš L. Human metabolites of cannabidiol: a review on their formation, biological activity, and relevance in therapy. Cannabis and Cannabinoid Res. 2016;1(1):90-101.
4. Epidiolex [package insert]. Carlsbad, CA: Greenwich Biosciences, 2018.
5. SAMHSA. Clinical drug testing in primary care (TAP 32). HHS. Rockville, MD, 2012.
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7. FDA. Press Release: Statement from FDA Commissioner Scott Gottlieb, MD, on new steps to advance agency’s continued evaluation of potential regulatory pathways for cannabis-containing and cannabis-derived products. April 2, 2019.
8. Bonn-Miller MO, Loflin MJE, Thomas BF, et al. Labeling accuracy of cannabidiol extracts sold online. JAMA. 2017;318(17):1708-1709.
9. Is CBD legal? Here’s what you need to know according to science. Public Broadcasting Service website. Available at: www.pbs.org/newshour/science/is-cbd-legal-heres-what-you-need-to-know-according-to-science. Accessed 01/18/2020.
10. Dowell D, Haegerich TM, Chou R. CDC guideline for prescribing opioids for chronic pain—United States, 2016. JAMA.2016;315(15):1624-1645.
11. Argoff CE, Alford DP, Fudin J, et al. Rational urine drug monitoring in patients receiving opioids for chronic pain: consensus recommendations. Pain Med. 2018;19(1):97-117.
12.Quest Diagnostics. Health Trends: Drug misuse in America 2019:physician perspectives and diagnostic insights on the evolving drug crisis. October 2019.
13. SAMHSA. Medication-assisted treatment for opioid addiction in opioid treatment programs. HHS. Rockville, MD, 2012.
14. Quest Diagnostics. Urine testing panels and cutoffs. Available at: www.questdiagnostics.com/ home/companies/employer/drug-screening/products-services/urine-test/urine-process-certifications. Accessed January 19, 2020.
15. Saitman A, Park HD, Fitzgerald RL. False-positive interferences of common urine drug screen immunoassays: a review. J Anal Toxicol. 2014;38(7):387-396.