Urine Testing for Detection of Marijuana: An Advisory
Within the past several years, two U.S. companies (SYVA Co., Palo Alto, California, and Roche Diagnostics, Nutley, New Jersey*) have introduced tests to detect traces of marijuana in urine. Concern about the effects of marijuana on a person’s ability to perform such tasks as driving, flying, or operating machinery has prompted various governmental and industrial groups to establish policies about marijuana use, which often include chemical screening of biologic fluids. Until recently, testing of plasma has been the only means by which exposure to marijuana has been detected. Three years ago, however, the first urine-screening test became available to make such screening possible at moderate cost (SYVA).
The urine test is based on detection of 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (9-carboxy-THC), a metabolite of delta-9-THC, which is the primary pharmacologically active component of marijuana. Studies involving humans indicate that 80%-90% of the total dose of delta-9-THC is excreted within 5 days–approximately 20% in urine and 65% in feces (1). Plasma concentrations of delta-9-THC peak by the time a smoked dose is completed and usually fall to approximately 2 ng/ml within 4-6 hours. 9-carboxy-THC is detectable in plasma within minutes after a dose is smoked and remains in plasma considerably longer than THC itself. Urine from marijuana users contains quantities of 9-carboxy-THC in both free and conjugated form, as well as other cannabinoids (THC and its metabolites) detectable by the test.
When the manufacturer’s instructions are followed, urine samples containing at least the stated detection level of 9-carboxy-THC will test positive at least 95% of the time. In a CDC field-test survey of 64 laboratories, those using the SYVA system for urine screening for cannabinoids had an incidence of 4% false-positive results (2); whether these errors were analytical or clerical in nature was not determined. The manufacturer states that any positive test result should be confirmed by an alternative method.
Only blood-sample measurements are likely to correlate with a person’s degree of exposure (3); attempts to correlate urine concentration with impairment or time of dose are complicated by variations in individual metabolism, metabolite accumulation in the chronic user, and urine volume changes due to diet, exercise, and age. Therefore, a positive result by the urine cannabinoid test indicates only the likelihood of prior use. Smoking a single marijuana cigarette produces THC metabolites that are detectable for several days with the cannabinoid assay (4). THC can accumulate in body fat, creating higher excretion concentrations and longer detectability. If an affect on performance is the main reason for screening, the urine cannabinoid test result alone cannot indicate performance impairment or assess the degree of risk associated with the person’s continuing to perform tasks. If a history of marijuana use is the major reason for screening, the urine test for cannabinoids should be able to detect prior use for up to 2 weeks in the casual user and possibly longer in the chronic user.
A chain of custody for the sample must be maintained by the testing laboratory, as well as during the steps that bring the sample to the laboratory. All urine samples positive by the cannabinoid assay need to be confirmed by an alternate method that is as sensitive as the screening test, a condition not always met. Methods employed for cannabinoid confirmation are gas chromatography (5), gas chromatography/mass spectrometry (6), and high performance liquid chromatography (7). Because of costs involved in more complex confirmatory procedures, confirmatory tests have not always been conducted to verify presumed positive test results. Since the screening tests are immunologically based and measure both conjugated and free forms of THC metabolites, any confirmatory procedure should either measure both forms or should include a hydrolysis step to increase analytical sensitivity. Confirmatory techniques may be specific for a particular THC metabolite, while the screening kits react with virtually all THC metabolites, a further complication in confirming screening results. SYVA markets two different cannabinoid assay kits with a twofold to fourfold difference in the amount of THC metabolite required to produce a positive test result. Regardless of which assay kit is used, test results should be interpreted by qualified personnel and positive results verified so that there is a very limited possibility of a false-positive result. Reported by Div of Preclinical Research, Div of Epidemiology and Statistical Analysis, National Institute on Drug Abuse; Div of Technology Evaluation and Assistance, Laboratory Program Office, CDC.
Editorial Note: Marijuana is the most widely used illicit drug in the United States; an estimated 50 million people have tried it at least once (8). A recent U.S. Department of Defense survey showed that chronic marijuana use exceeded 30% among some members of the Statistical Analysis, National Institute on Drug Abuse; Div of Technology Evaluation and Assistance, Laboratory Program Office, CDC. Editorial Note: Marijuana is the most widely used illicit drug in the United States; an estimated 50 million people have tried it at least once (8). A recent U.S. Department of Defense survey showed that chronic marijuana use exceeded 30% among some members of the military. Although further study is needed on the long-term health effects of marijuana use, short-term effects include impaired motor coordination and perception, as well as slowed learning and decreased short-term memory (9).
Urine cannabinoid assays permitting extension of testing to nonlaboratory settings, such as industrial sites, probation offices, and schools have been developed. The relative ease with which the test can be performed encourages its use by nontechnical personnel.
Those who interpret data from laboratory or nonlaboratory settings should be aware of possible pitfalls in such testing (10). Whether test results are used for counseling or determining compliance with orders to desist from marijuana use, the laboratory must perform the and schools have been developed. The relative ease with which the test can be performed encourages its use by nontechnical personnel.
Those who interpret data from laboratory or nonlaboratory settings should be aware of possible pitfalls in such testing (10). Whether test results are used for counseling or determining compliance with orders to desist from marijuana use, the laboratory must perform the test according to the manufacturer’s recommendations, including confirmation of any positive test results. A recent report indicates that passive inhalation of marijuana smoke by a nonuser is not likely to produce a positive urine test result (11), but since some passive inhalation does occur, establishment of minimum sensitivity limits by a laboratory must be done cautiously.
Hunt AC, Jones RT. Tolerance and disposition of THC in man. Pharm Exp Ther 1980;215:135-44.
Hansen HJ, Lewis DS, Boone DJ. Marijuana analysis: results of a recent interlaboratory survey. Clin Chem 1981;27:1104.
Hawks RL. Developments in cannabinoid analyses of body fluids: implications of forensic applications. In: Agurell S, Dewey W, Willett RE, eds. The cannabinoids: chemical, pharmacologic and therapeutic aspects. New York: Academic Press, 1983 (in press).
Clark S, Turner J, Bastiani R. EMIT cannibinoid assay. (Clinical study no. 74, summary report). Palo Alto, Calif.: SYVA Co., 1980:17-8.
Whiting JD, Manders WW. Confirmation of a tetrahydrocannabinol metabolite in urine by gas chromatography. J Anal Tox 1982; 6:49-52.
Foltz RL, Hidy BJ. Quantitative analysis for delta-9-THC, 11-hydroxy-delta-9-THC, and 9-carboxy-delta-9-THC in plasma using GC/CI-MS. In: Hawks R, ed. Analysis of cannabinoids. Research monograph 42. Rockville, Maryland: National Institute on Drug Abuse, 1982.
ElSohly MA, ElSohly HN, Jones AB. HPLC analysis of the major metabolite of delta-9-tetrahydrocannabinol in urine. J Anal Tox 1983 (in press).
Fishburne PM, Abelson HI, Cisin I. National survey on drug abuse: main findings, 1979. Washington, D.C.: U.S. Government Printing Office, 1980. (HHS publication no. (ADM) 80-976).
Institute of Medicine. Marijuana and health. Washington, D.C.: National Academy Press, 1982:1-5.
McBay AJ, Dubowski KM, Finkle BS. Urine testing for marijuana use. JAMA (letter) 1983, 249:881.
Perez-Reyes M, Guiseppi SD, Mason AP, Davis KH. Passive inhalation of marijuana smoke and urinary excretion of cannabinoids. Clin Pharmacol Ther 1983; 34:36-41.
Does CBD Show Up on a Drug Test?
Is it possible to fail a drug test for using CBD? As the metabolites of cannabinoids go from the bloodstream and even into one’s hair follicles, it is possible to test positive for CBD up to three months after last ingestion. Testing positive on a drug test becomes likelier for people who frequently consume full-spectrum CBD products.
Learn more about how you can use CBD and still pass a drug test. Plus, discover the benefits of a medical marijuana card before you head into your scheduled drug screening.
Download Free Guide to CBD
CBD and Drug Tests
Most drug screenings do not directly test for CBD. Instead, most drug screenings test for the following:
Of course, it is possible for a person to have a prescription for drugs in some of the above drug classes, in which case it is likely that a positive test will be assessed by a medical review officer (MRO). Such a scenario could lead to a drug test failure, so be sure to speak with your doctor if you are taking any prescription medications.
Reasons for Failing a Drug Test While Using CBD
If a CBD product contains over 0.3% THC and is used regularly, it is possible for THC to become detectable. People who often take full-spectrum CBD oils, even if the products contain minimal amounts of THC, could possibly test positive for THC.
Some people reduce this risk by using CBD isolates and oils that test nil for THC, but this strategy can reduce the efficacy of CBD to some extent. However, if a CBD product contains 0.3% or less of THC, even regular consumption of high levels of CBD (say 1,000 milligrams (mg) or over) rarely meets the threshold for a positive THC result, which is >50ng/ml in the urine.
How to Use CBD and Pass a Drug Test
While CBD is not usually looked for in most drug tests, it is still possible that you may test positive for THC, even if you do not consume it or only use small amounts. The best way to prevent a false positive is by doing the following:
Use 0% THC Products
The only way to guarantee that THC stays out of your system is to select a CBD isolate product. Genuine CBD isolates contain 0% THC and should not register on any standard drug screening.
Stop Using CBD 2 Weeks Before Test
Refrain from using any CBD product for at least two weeks prior to any test. Ideally, stop using CBD one month or even two months to be sure that your drug screening doesn’t yield a false positive result.
Be Active and Exercise
Getting plenty of exercise and keeping hydrated may help "flush" your system of any cannabinoids. Burning away fat cells that contain cannabinoids via exercise may prove particularly effective. Going to the sauna a day or two prior to the test may help as well.
However, it is not proven whether or not you can "flush" cannabinoids out in this manner. Exercise can increase plasma THC concentrations in regular users , at least in the short-term, as exercise releases dormant THC stored in fat cells. Theoretically, this means that reducing cannabinoid use while keeping active can get rid of cannabinoids stored in fat. Stress and diet can also play a part in the extent to which fat in the body stores cannabinoids.
Some people claim that drinking plenty of green, white and herbal teas can help detoxify the system. Whether this is true or not we cannot say for sure, but it is interesting to note that tea catechins have a weak affinity for cannabinoid receptors . Like beta-caryophyllene, some types of tea could be said to be a " dietary cannabinoid ."
Such teas also tend to contain plenty of antioxidants, so sipping your favorite matcha could also help "flush" cannabinoids out of your body as well as providing an alternative way to stimulate your endocannabinoid system (ECS) .
Medical Marijuana Card Protections
As cannabis and CBD are Schedule I substances , federally illegal and cannot be prescribed outside of the Schedule V, FDA-approved Epidiolex, a medical marijuana card cannot "save" you. However, some states are starting to add employment protections for people who need to use cannabinoid-based medications.
If you are not working with heavy machinery or driving, not working with individuals considered vulnerable, or not working within law enforcement or any other form of federal employment, then there may be some leeway. These exceptions, however, depend very much on the employer’s discretion.
Having a valid medical marijuana card will likely give you access to a greater number of high-quality, cannabis-based (rather than hemp-based) CBD. There may be slightly higher levels of THC (though not necessarily psychoactive amounts) in some of the CBD-based cannabis products when compared to hemp products, but having a valid MMC may lend credence to the fact that you may need to use cannabis for a defined and diagnosed medical problem.
Frequently Asked Questions
How long is CBD detectable in urine?
In the urine, CBD is detectable for between five and 10 days after last ingestion. However, as it would be the metabolites of CBD (7-OH-CBD and 6-OH-CBD) that are tested for and cannabinoid metabolites bind to the fats in the body, CBD can be detectable in the urine for two to five weeks after ingestion, depending upon the regularity of use and dosage .
Do drug tests look for CBD?
At the moment, most standard and even more advanced drug tests do not test for CBD. But the cannabinoid can be detected if the right tests are conducted. Levels of CBD in the bloodstream usually peak within three to five minutes after ingestion if smoked or vaped, and between 30 minutes and two hours if taken sublingually or eaten. The effects usually last between four and 12 hours, depending on the method of ingestion, the amount taken and the individual’s metabolism.
For many people, CBD itself is not hugely intoxicating, although some may feel sedative effects in high doses, especially when combined with high concentrations of myrcene .
Will I pass a DOT drug test using CBD oil?
The Department of Transportation (DOT) screens prospective employees for marijuana use rather than for CBD consumption. Therefore, unless you have been consuming very high amounts of full-spectrum CBD (that contains trace amounts of THC), it is unlikely that you will fail a DOT drug test.
To experience the benefits of CBD and other cannabis products, apply for your medical marijuana card through Leafwell today.
Article written by
Tina Magrabi Senior Content Writer
Tina Magrabi is a writer and editor specializing in holistic health. She has written hundreds of articles for Weedmaps where she spearheaded the Ailments series on cannabis medicine. In addition, she has written extensively for the women's health blog, SafeBirthProject, as well as print publications including Destinations Magazine and Vero's Voice. Tina is a Yale University alumna and certified yoga instructor with a passion for the outdoors.
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How long does CBD oil stay in your system?
Cannabidiol (CBD), a non-intoxicating compound found in the cannabis plant, may potentially relieve mild pain and anxiety. While many people are using CBD for these potential benefits, the fear of failing a drug test looms large for others. Because even with the legalization of hemp-derived CBD products in the US, there’s still some uncertainty about how CBD interacts with the body.
Here, we’ll cover the existing research on CBD and its interaction with the human body as well as what factors can affect how long CBD stays in your system.
How long does CBD stay in your system? That depends on multiple factors. Photo by: Gina Coleman/Weedmaps
How long does CBD oil stay in your system?
CBD may not produce the same intoxicating effects as THC, but it does get stored in the body. The time that CBD remains detectable in the body depends on several factors.
- Metabolism: A person’s metabolism plays a prominent role in how fast CBD is metabolized and eventually excreted from the body.
- Frequency of use: Using CBD frequently will also influence the amount of time it remains in the body.
- Dosage: A large amount of CBD taken at a time will influence how long the cannabinoid remains in the system.
- Method of administration: Both the effects of CBD and its presence in the body are contingent on how the cannabinoid is introduced into the body. For instance, smoking or vaping CBD allows it to take effect almost immediately, while ingestion will delay the onset for an hour or two.
A 1991 study published in Pharmacology Biochemistry & Behavior examined the concentration of CBD in the blood after high doses daily. Over a six-week period, the research team administered a daily dose of 700 milligrams of CBD to 14 Huntington’s disease patients. One week after the dosing ceased, the CBD remaining in the blood was just 1.5 nanograms per milliliter and was “virtually undetectable” thereafter.
A 2018 review of existing CBD studies found that the estimated half-life of CBD was two to five days for those who took a daily oral dose. Other delivery methods delivered varied half-lives.
Bottom line: While the time that CBD is detectable in the body will depend on the aforementioned factors, we can deduce that CBD will likely leave the system after a week or two.
While the time that CBD is detectable in the body will vary, we can deduce that CBD will likely leave the system after a week or two. Photo by: Gina Coleman/Weedmaps
How long is CBD detectable in urine?
We have some insight into how long CBD remains in the blood, but there is little research on how long CBD is detectable in urine. In a 2016 study published in the Journal of Pain, participants were given different types of CBD-rich cannabis products, including oils, capsules, and flower. Two hours after administration, urine samples from all 15 subjects tested positive for CBD. The researchers followed one participant after the last day of administration and found that CBD was no longer detectable in the urine after 24 hours.
It’s important to note that, while existing evidence shows us that CBD can definitely be detected in the body for a certain period of time, most drug tests specifically look for the presence of THC. Therefore, accurate information on how long CBD stays in the body remains limited compared with information on THC.
Bottom line: Apart from the one study that showed CBD was no longer detectable in urine after 24 hours, there isn’t much research on drug testing for CBD in urine.
How long do CBD oil effects last?
The consumption method plays a crucial role in determining how long it will take to feel the effects of CBD and how long they will last.
Oral ingestion is the most common method of CBD consumption. Administering a couple of drops of CBD oil directly into the mouth is certainly a convenient way to reap the potential benefits of this therapeutic cannabinoid. However, ingestion is not necessarily the most effective consumption method for those who want to feel the effects of CBD immediately.
Swallowing CBD oil prevents the cannabinoid from entering the bloodstream right away. Instead, it will travel first through the digestive tract and eventually on to the liver, where it will be broken down before finally reaching the bloodstream.
With ingestion, it could take anywhere from one to two hours before the effects of CBD finally set in. Photo by: Gina Coleman/Weedmaps
Studies show that when the liver metabolizes CBD compounds, they undergo what is called the “first-pass effect.” Enzymes in the liver reduce CBD concentration before the remainder is finally sent to the bloodstream and circulated throughout the body. While oral consumption of CBD has become popular for its ease of use, it can be an inefficient method of consumption compared with inhalation or sublingual administration. This is because only about 5% of swallowed CBD ends up in the bloodstream, meaning this method provides low bioavailability.
Bottom line: Whether you’re ingesting CBD oil or CBD-infused edibles, it ultimately goes through the same lengthy digestive process, reducing the total CBD concentration in the bloodstream. With ingestion, it could take anywhere from one to two hours before the effects of CBD finally set in. From there, you may feel the effects for one hour to several hours, depending on the dose and your response to CBD.
The sublingual method is considered to be more effective than ingestion. CBD oil can be consumed sublingually by placing a few drops under the tongue and holding it for two to four minutes, then using the tongue to rub it into the tissue under the tongue and on the inside of the cheeks before swallowing the remainder. Using this method, CBD is transferred to the bloodstream via the mucous membranes located in the mouth, completely bypassing the digestive system and liver.
Consuming CBD products sublingually leads to higher bioavailability compared to consuming CBD products orally. Photo by: Gina Coleman/Weedmaps
Bottom line: Consuming CBD products sublingually leads to higher bioavailability compared to consuming CBD products orally. Depending on the dose and your response to CBD, the effects from sublingual consumption should kick in within 30 minutes and last for one to three hours.
Inhalation is also an effective delivery method for CBD due to its rapid absorption and the efficiency of the lungs at transferring CBD into the bloodstream. Whether you’re smoking a high-CBD strain or taking a draw from a CBD vape pen, the interaction with the body remains the same. When CBD is inhaled, the cannabinoids are sent directly to the lungs, where they are rapidly absorbed into the bloodstream and put into circulation.
Inhalation, via CBD vapes or smokable flower, is also an effective delivery method for CBD. Photo by: Gina Coleman/Weedmaps
Bottom line: Existing evidence suggests that CBD reaches peak blood concentration within three minutes after inhalation, meaning any effects should be felt shortly after use. The effects should then last anywhere from 45 minutes to a couple of hours.
Will CBD show up on a drug test?
In most cases, it’s highly unlikely that CBD will cause a positive test result in a drug screening. Most drug tests are developed to look specifically for the presence of THC or related substances. On top of that, employers generally abide by the Substance Abuse and Mental Health Services (SAMHSA) guidelines, which include detection for THC but not CBD.
Keep in mind that even hemp-derived CBD products are legally allowed to contain up to 0.3% THC. This could cause hesitation for some CBD-curious consumers who don’t want THC in their system or risk a false positive result on a drug test. However, the chances of failing a drug test from using hemp-extracted CBD oil are extremely slim. You would need to take an exorbitant dosage of full-spectrum CBD oil (estimates range from 1,000 to 2,000 milligrams per day) to risk a positive drug test result.
Consumers who want to be extra-cautious and use CBD with no THC should shop for a broad-spectrum oil or a CBD product that contains pure CBD isolate. Broad-spectrum oil is refined to exclude THC, while CBD isolates contain no THC or other plant-based cannabinoids. To ensure that your CBD contains no THC, it’s important to source products from reputable manufacturers that provide a certificate of analysis from a third-party testing lab.
Consumers who want to be extra-cautious and use CBD with no THC should shop for a broad-spectrum oil or a CBD product that contains pure CBD isolate. Photo by: Gina Coleman/Weedmaps
Based on existing research, CBD may stay in your system anywhere from 24 hours to a few weeks. That timeframe can change depending on a variety of factors including metabolism, consumption method, frequency of use, and dosage.
For those concerned about drug tests, there are different types of drug tests with varying detection thresholds for THC. The most commonly used drug screening method is the urine test, which typically has a lower threshold for detection. Under the SAMHSA framework, the cutoff limit for the presence of THC is 50 nanograms per milliliter. A nanogram is one-billionth of a gram. Given the research, it would be very unusual to fail a drug test after consuming licensed, lab-tested CBD products.