THC PreDosage test (3 detection levels)
• Screening of marijuana (weed, hashish, oil. )
• Semi-quantitative detection: 18 + 50 + 150 ng/ml.
- Reference : DOA-M03-9B
- Type : Urine test
- Manufacturer : NarcoCheck®
- Reliability : ≈ 99%
- Results in : 5 minutes
- Time of detection : 2 to 30 days
- Cut-off : 18 + 50 + 150 ng/ml
- Packaging : Boxes of 25 tests
- Standard : CE 98/79
- Format : Dipcard
- Origin : Made in France
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This rapid test is made for the semi-quantitative detection in human urine of THC (marijuana, cannabis)
3 levels of detection in a single test !
This test does not only deliver a simple positive or negative result.
It shows in addition if the concentration of THC in urine is LOW, MEDIUM or HIGH.
This test is particularly effective over time. Initial screening will serve as a baseline, while the tests that follow will see the lowering or raising level of THC in urine. By practicing regular screenings, it is now much easier to see if the subject has stopped its consumption (steady decrease in the level of THC) or if he can get re-smoking (sudden increase in the level of THC).
A new tool to assist a patient or the progress of a withdrawal.
The advantages of THC PreDosage:
Encourage and motivate those who decide to give up marijuana is an integral part of the assistance they need. This is one of the major advantages of this test: it allows the patient to see by himself that his metabolism is eliminating the residues of THC. Efforts are therefore represented by a real and practical tool, which helps to maintain motivation, because it is possible to say “Look, your efforts are useful! Your THC is decreasing. Hang in there, it works! “
This test can detect the presence of any cannabinoid :
- Marijuana (indoor or outdoor weed)
- Cannabis resin, also known as hashish
- Cannabis oil (rarely used)
It is effective whatever the mode of consumption :
- In joints (marijuana cigarettes).
- By inhaler, bang etc.
- In infusion or culinary preparations like cakes (also called “space cake”)
Detection levels :
NarcoCheck® THC PreDosage test (3 detection levels)
|THC Level 1||18|
|THC Level 2||50|
|THC Level 3||150|
This test will be positive for cannabis on Level 1 if the sample tested contains at least 18 nanograms of THC per milliliter of urine, positive on Level 2 if the THC rate is greater than 50 nanograms per milliliter of urine, positive at Level 3 if the THC rate is greater than 150 nanograms per milliliter of urine, or totally negative if the sample contains less than 25 ng/ml or not at all.
Detection time of THC (cannabis active substance) in urine :
Does CBD Ruin Your Drug Test?
Learn if CBD will show up on your drug test. First, lets look at what CBD really is; CBD (cannabidiol) is one of the second most frequently used active ingredients of hemp. CBD is derived directly from hemp plant, a relative of Cannabis sativa.
CBD is the main active ingredient in hemp and does not cause a “high.” There have been no reports to suggest pure CBD could cause any health related issues.
CBD is a very popularly used natural remedy for many common ailments because of its anti-inflammatory, pain-relieving and anti-anxiety properties. It is also used for insomnia as a sleeping aid. CBD can be found in the market in many forms such as CBD oil, edibles, tinctures, vape oil, sublingual drops, pills, capsules, creams, latte, lotions, etc.
CBD aids in the treatment of mental health conditions such as depression and anxiety because of its psychotropic effects, but does not have similar intoxicating features of THC.
Both THC and CBD are elements of a chemical class called cannabinoids. Cannabinoids are plants oils, and cannabis is loaded with more than 100 versions of them. THC might show up in your standard 5 panel drug test but CBD does not show up.
It should be noted that hemp is almost devoid of THC, a chemical in weed that causes a high. Legally, hemp should not contain more than 0.3% THC to be considered hemp.
Is CBD Hemp-Derived or Weed-Derived?
CBD can be derived either from Cannabis sativa or Cannabis Indica plants. Hemp is Cannabis sativa whereas weed is either Cannabis sativa or Cannabis indica.
The hemp plants usually produce more of CBD while weed plants produce more of THC. Therefore, there is a substantial difference between hemp-derived and weed-derived CBD products. The hemp-derived CBD contains less than 0.3% of THC while the weed-derived CBD contains 0.3% or more THC.
Hemp-derived CBD products are federally legal as long as it contains less than 0.3% THC, thus lower chances of side-effects and addiction.
If CBD is not extracted properly, it could contain higher concentrations of THC, which may possibly show up on a drug test. Some hemp-derived CBD products end up containing more than 0.3% THC due to minimal FDA regulations.
Can CBD Surface on a Drug Test?
CBD does not show up on a drug test, but THC compound present in CBD products will cause a positive result.
Most CBD products contain trace amounts of THC (an active element of weed). A drug test can detect the presence of THC in the body if CBD products are consumed on a regular basis. The product’s quality and composition also matters.
According to Food and Drug Administration (FDA), products containing more than 0.3% THC are illegal and the United States Drug Enforcement Agency (DEA) has classified them as a Schedule I drug.
Most CBD products are not regulated and standardized. Thus, it is difficult to find the ingredients present in the cannabidiol even if they are legally approved in the United States. The factors such as CBD harvesting and CBD extraction may also lead to THC contamination. Some types of CBD tend to have less amounts of THC in them compared to others.
Different Types of CBD
Cannabis plants contain hundreds of compounds that occur naturally including:
The chemical composition may vary according to the plant variety and breed. Harvesting and refining process can also change the compounds appearing in CBD.
Different Types of CBD Extracts
1. Full-Spectrum CBD
- Full-spectrum CBD extracts contain all the naturally occurring compounds in the plant after extraction. In other words, the extracts contain CBD, terpene, flavonoid and other cannabinoids such as THC.
- Full-spectrum CBD is usually extracted from weed subspecies.
- Weed-derived CBD oil may have variable amounts of THC.
- Hemp-derived CBD oil needs to have less than 0.3% THC legally.
- Most manufacturers do not furnish details about the extract derivativeness, so it is difficult to evaluate THC quantity in the given product.
- Full-spectrum CBD products are available in the form of oils, edibles, tinctures, topical creams and serums.
2. Broad-Spectrum CBD
- Broad-spectrum CBD products contain additional compounds including terpene and other cannabinoids found in the plant.
- During refining, all of the THC compounds are removed.
- Broad-spectrum CBD is not widely available and often sold in the form as oil.
3. CBD Isolate
- CBD isolate is the purest form of CBD and all the additional compounds from the plant are refined after extraction.
- CBD isolate is typically extracted from hemp plants.
- Hemp-based CBD isolates does not contain THC.
- CBD isolate products are available in the form of oil, tincture, crystalline powder or small solid blocks that can be consumed by breaking it into pieces.
It must be noted that products labeled “THC-free” may still contain traces of THC. It’s advisable to check the packaging labels.
Some of the potential therapeutic effects of CBD are:
- Reduces inflammation
- Prevents nausea and vomiting
- Relieves pain
- Controls anxiety, psychosis
- Promotes neuro-protection
CBD is assumed to boost serotonin levels in the brain and provoke the production of new neurons in the hippocampus, where emotions and mood evolve. Though this theory is not yet proven, CBD manufacturers market their products with promotional statements regarding its therapeutic benefits.
Approved CBD should contain less than 0.3% THC. Not all CBD products disclose their complete list of ingredients and consumers may not be aware of additional components, which may cause side effects.
Does CBD Show Up on a Drug Test?
CBD doesn’t show up on the drug test because there are no tests specifically designed to detect its presence in the body. The U.S. Drug Enforcement Administration (DEA) and the Controlled Substances Act forbids the possession of weed and states that CBD is not considered an illicit substance. The target is THC, which is the active psychotropic agent in weed.
Drug tests screen for THC or its metabolites. Passing a drug test doesn’t mean that there isn’t any THC or its metabolites present in the system. A negative drug test suggests that the amount of THC is below the cut-off level.
Different drug testing methods have different cut-off values and detection windows.
1. Urine Drug Testing
- This is the most commonly used drug testing method for cannabis, especially in workplace.
- In urine, a concentration of 50 ng/mL for THC will trigger a positive test.
- THC metabolites can be detected in urine for approximately 3 to 15 days after last use.
- Detection windows vary according to dose and frequency of use.
- The more frequent the cannabis use, the longer the detection period; more than 30 days.
2. Blood Drug Testing
- THC gets quickly eliminated from the bloodstream, so blood tests are less commonly used for workplace drug screening.
- THC can be detected in the plasma for up to 5 hours and THC metabolites for up to 7 days.
- Blood tests can indicate current impairment, such as driving under the influence.
- THC concentration in blood of 1, 2 or 5 ng/mL indicates impairment in cannabis legalized states, whereas other states have zero-tolerance policy.
3. Saliva Drug Testing
- Saliva testing is not a commonly used method for THC testing.
- No established cut-off limits for THC detection in saliva.
- THC can be detected in oral fluids for about 72 hours. In heavy and chronic use, it may be detectable for much longer period.
4. Hair Drug Testing
- Hair testing is also not a commonly used method for THC testing.
- No established cut-off limits for THC metabolite detection in hair.
- Private industries follow cut-off limit of 1 pg/mg for THC-COOH.
- THC metabolites can be detected in hair for up to about 90 days.
What might cause CBD use to result in a positive test result for THC?
CBD use can lead to a positive drug test result due to some of the possibilities below:
- Cross-Contamination: This can occur during manufacturing process even if only trace amounts of THC are present. Products labeled “CBD only” may contain traces of THC if it’s around other substances containing THC.
- Secondhand exposure to THC: Positive drug test result may occur if exposed to secondhand weed smoke. There are research studies indicating the absorption of THC via secondhand smoke depend on the size of the weed, potency and ventilation of the area.
- Product mislabeling: CBD products are not systematically regulated and no proper protocols to test their actual composition. Research studies indicate that some CBD-only products did contain THC in them. So, product mislabeling is also common in this industry.
- Reagents in Drug Tests Can Convert CBD into THC: Some labs still use the GC-MS method to analyze drugs that are nonvolatile, polar or thermally labile. To identify drugs easily, certain reagents are added to the specimens and run through the GC-MS machine. The CBD gets converted into THC under acidic conditions. Hence, if a person has been consuming only CBD and not THC, then this test may report a false positive for THC.
Can CBD transform into THC in the body?
CBD can turn into THC under acidic conditions. There are speculations that this chemical transformation also occurs in the human stomach.
Earlier in-vitro studies in 2016 indicated that simulated gastric fluid could turn CBD into THC. But it was later concluded that in-vitro conditions don’t represent the actual conditions and similar transformation doesn’t appear to occur in a human stomach. It was also pointed out that there were no reported side effects of CBD similar to those associated with THC.
How to ensure a CBD product doesn’t contain THC?
If considering using CBD, it is important to do extensive research on the products available. There are some CBD products that are safe to use.
Before purchasing a CBD product, remember to:
- Read information about the product
- Check if the product is hemp-derived or weed-derived
- Check if the CBD is full-spectrum, broad-spectrum or CBD isolate (pure)
- Opt products that list the amount of CBD
- Check for concentration of CBD per dose (may vary for different products such as oil, tincture, edible, lotions and so on)
- Check the place of manufacture for hemp-derived CBD products
- High concentrated CBD products are generally very expensive irrespective of their size and quantity compared to other products.
- Start using a low-dose product if possible and then gradually move on to higher doses.
Of note, the CBD products derived from weed and full-spectrum CBD products derived from hemp are more likely to contain THC. The quality of hemp varies in different states. Colorado and Oregon are most reputable states and have longstanding hemp industries and rigorous testing guidelines. Opting hemp-derived CBD products from these states may be beneficial.
How to Address a Positive THC Test if using CBD Products?
In general, initial drug tests do not measure the quantity of a drug. If suspected failed drug test due to CBD use, sensitive method such as GC-MS or RP-HPLC can be done to confirm the result. Confirmatory tests are used to identify specific drug and the amount of metabolite present.
Does CBD Vape Oil Show Up On The Drug Test?
There is no evidence to suggest CBD has caused any false positives, but CBD products with high THC content can contribute to positive drug test.
Accidental THC exposures from CBD products are not unusual. People who ingested CBD-infused gummy bear have tested positive for THC as well as people who claimed to have used CBD only products.
People who vaped pure CBD and consumed pure CBD capsules did not get positive results. Studies also show that people who use legal hemp-derived products for medical intent rarely do not test positive, but repeated use may accumulate THC and its metabolites in the system.
Since the popularity of using CBD is growing quickly, people should be wary of single dose or cumulative THC exposure as these now legal products may cause an unexpected positive drug test.
Regulation of 9-THC content and accurate labeling in CBD/hemp products may prevent unexpected positive result on a drug test and inadvertent drug effects.
Regular users of CBD vape oil should take necessary steps to avoid a positive drug test. They can use high quality CO2-extracted CBD vape juice. They should check for the THC concentration in the vape oil before they purchase.
Vaping is considered less harmful than smoking because of its low toxicity. CBD also aids in the recovery from habituation such as smoking cigarettes.
Is There a Drug Test For CBD Oil?
An average drug test will not screen for the presence of CBD. Since CBD is a chemical substance that the body metabolizes, specific test can be formulated for detection.
To conduct a CBD oil drug test in specific, the company or an entity has to pay extra amount to the testing agency in order to change their testing process to include CBD. If this non-intoxicating compound does not affect employee’s ability to work, then it is not required to have a CBD oil drug test.
Individuals using CBD products must ensure that they consume high-quality CBD products that have zero THC such as crystalline powder or distillate products to pass the drug test.
Can you fail a drug test due to CBD use?
A person can fail a drug test if consumes CBD product that contains THC and its metabolites. For CBD to be legal, it should be approved with certified strains of less than 0.3% THC. Even though these THC concentrations will not have any effect on the cognitive function, it might be detected in the normal drug test.
According to the SAMHSA standards, the recommended THC cutoff level is 50 ng/mL to pass a drug test. Most CBD products are usually sold with lower levels of THC, so most CBD consumers won’t find it difficult to pass a drug test. If CBD or hemp oil is consumed at high levels, there may be a possibility of false positive result on a drug test. In the event of a false positive result, a follow-up test can provide more definitive results.
Each drug test has different detection threshold limits. There are certain parameters such as frequency of CBD usage, strength of CBD oil and the person’s ability to metabolize the cannabinoids used to determine the trace amounts of THC.
To avoid testing positive for traces of THC and its metabolites, one should:
- Drink lots of water to stay hydrated before taking the test.
- Stop taking weed for four to six weeks before testing.
- Stop taking CBD with THC compound for at least a week before the test.
NOTE: If hair and nail specimens are collected as part of testing, it may yield a positive result for traces of THC due to their longer detection period.
In general, no person will fail a drug test because of CBD, but may fail in some cases due to THC residue in the CBD product. Usually, drug testing companies mainly look for the traces of THC, which is the main active ingredient in weed. Other factors such as CBD dosage and length of use, and polypharmacy may influence the success or failure of a drug test.
How Long Does CBD Stay In Your System?
In general, CBD stays for around 2 to 5 days in the human body depending on its usage. People use CBD either by ingesting, inhaling or applying CBD topically. Most people take an oral supplement such as CBD oil drops or use CBD emollients.
It usually takes 20 to 30 minutes for the CBD oil to take effect after ingestion. The length of time it takes to leave the body depends on several factors including serving size, administration route (edibles, vaping, oil, tincture, etc.), taken with food or on an empty stomach, weight, age, etc.
CBD may take between 1 to 2 days or on the outside of 4 to 25 days to leave the system though there aren’t many reliable studies to determine this. There are determinations that urine test can detect THC metabolites between 10 to 15 days if used daily, may vary depending on the serving and usage frequency.
How Does the Body Process CBD?
People who consume CBD orally, the digestive system first processes the compound, it goes into the stomach and then ending up in the liver. Some of the CBD molecules are broken down by the liver and the rest is passed on to the bloodstream.
Some people place a few drops of CBD under their tongue. Here, the membranes in the mouth transfer this compound directly into the bloodstream, bypassing the liver. This is quite effective in getting most benefits out of the CBD oil.
Some people inhale CBD. After inhalation, the compounds get absorbed through the lungs (alveoli). Then the CBD molecules are sent directly to the bloodstream. However, it should be noted that vaping can cause internal injuries and even death.
After ingestion, the CBD molecules reach the bloodstream and the liver sorts through all the compounds and metabolize for disposal. The metabolites are eliminated out of the body system through urine or feces.
When used topically, most of the CBD never enters the bloodstream. It affects the skin receptors that render localized improvements in skin health.
There are several factors that determine the timeframe the CBD remains detectable in the body, to include:
- Metabolism: Metabolism plays a key role on how fast the CBD metabolism takes place and eliminated from the body. There may be variations in CBD effects if taken with food or on an empty stomach. Certain foods can increase bioavailability and overall CBD concentration in the body.
- Frequency of CBD Use: The frequency of CBD usage will also determine the time period it remains in the body.
- CBD Dose: The amount of CBD taken at a time will determine how long it remains in the system.
- Method of Administration: The CBD effects and the presence of CBD in the system will depend on how the cannabinoid goes into the body. The effect of smoking or vaping CBD is almost immediate, whereas when taken orally, the onset of effect will be after an hour or two.
- Drug Interaction: CBD may interfere with the metabolism of other drugs, thus speeding up or prolonging the time to excrete CBD from the body.
- Age: Age also plays a vital role in metabolism. Older people may metabolize CBD compounds slower than young people do.
Single-use CBD, even if taken highest dose, does not stay in the system for more than 7 days. However, in chronic and heavy users, it may take a week or more for the CBD to be completely eliminated out of the body. If the CBD is not completely excreted from the body after each use, the concentrations may accumulate overtime in the bloodstream and fat storage.
Points to Ponder
- Most CBD products are hemp-derived and contain THC less than 0.3%, which is federally legal.
- Weed-derived CBD contains 0.3% or more THC, so it is federallyillegal .
- Identify the amount of THC present in CBD products before purchasing. THC should be nil or less than 0.3%.
- Many CBD products are commercialized for medical purposes due to minimal regulations by the Government.
- Opt for pure CBD products to get most benefits.
- Find out if the CBD product is contaminated with higher amounts of THC.
Though THC less than 0.3% is legal, different types of drug tests still follow variable thresholds for detecting THC. For example, an average urine drug test detects THC if cut-off level is above 50 ng/mL. Though consuming pure CBD with THC less than 0.3% has least chances of producing a positive urine drug test, one can still get a positive urine drug test if the amount of THC consumption exceeds 50 ng/mL.
CBD may yield a positive THC test if certain reagents are added during GC-MS analysis. The CBD gets converted into THC under acidic conditions, which contributes to a false-positive result for THC.
If an employee fails the drug test due to CBD use, confirmatory test such as GC-MS or RP-HPLC can be done for conclusive results.
Cases in Urine Drug Monitoring Interpretation: How to Stay in Control (Part 2)
This is the second case in a series focusing on the differences between presumptive and definitive urine toxicology analysis, with a focus on the opiate and cannabinoid immunoassays.The first case 1 reviewed basic principles of urine drug monitoring (UDM), including its role in pain management, testing types, sample validity, and cut-off concentrations.
A 61-year-old female with chronic shoulder arthritis and back pain related to spinal stenosis presents to her pain management physician’s office with concerns regarding a cannabidiol (CBD) oil product. The patient underwent a routine urine drug screen for her job and was fired due to a positive result for tetrahydrocannabinol (THC). The patient has been using CBD oil that she purchased online for the past 6 months to help with her pain. The patient does not use marijuana. Prescribed medications include pantoprazole for gastroesophageal reflux disease (GERD), lisinopril for hypertension, rosuvastatin for hyperlipidemia, and oxycodone/acetaminophen 5 mg/325 mg every 6 hours as needed for pain. These disease states are all controlled on her current regimen. The patient’s immunoassay results are shown below.
Window of Detection
As discussed in the first case in this series, 1 several factors may determine the window of detection, including pharmacologic characteristics of the substances being analyzed as well as patient-related factors. 2 The window of detection in urine for most opioids, regardless of duration of use, is between 1 to 3 days. Methadone, with a variable half-life of 15 to 60 hours and significantly elevated half-lives in generic outliers, may be detectable for up to 11 days. 2,3 Detection of heroin is not generally made through a report of heroin in the urine because it is only present for up to 30 minutes after use. 4 In individuals using heroin, it is common to see a positive result for opiates on the urine drug screen for morphine present after definitive testing. Heroin’s metabolite, 6-monoacetylmorphine (6-MAM), may be detected for approximately 8 hours, 5 and is then metabolized into morphine which remains detectable for up to 3 days (see Table I). Detection of marijuana in the urine depends on the quality of the substance, frequency of use, duration of use, the individual’s fat content (since THC is stored in fatty tissue), and the hydration status of the individual being tested (see Table II). 2
Cannabidiol forms several metabolites, including: 6-OH-CBD, 7-OH-CBD, and 7-COOH-CBD. It is metabolized primarily by CYP3A4 and CYP2C19 which places it at risk for drug interactions with inhibitors/inducers of these enzymes. Furthermore, CBD may inhibit CYP2C8, CYP2C9, CYP2C19, and CYP1A2, as well as induce CYP1A2. 6-7 Although there are many different CBD products available, there are not many studies available regarding the window of detection for CBD and its metabolites.
There is limited information available on CBD pharmacokinetics, so let’s use pharmaceutical CBD (Epidiolex) as a starting point. Pharmaceutical cannabidiol has a half-life of 56 to 61 hours after seven days of twice-daily use, has very little renal excretion, and due to its long half-life, may be detectable in urine drug monitoring for approximately 12 days. 7
This case explores differences between presumptive and definitive urine toxicology analysis, with a focus on the opiate and cannabinoid immunoassays. (Source: 123RF)
Opiate assays are meant to detect natural opiates that are structurally related to morphine and morphine metabolites. These include heroin, morphine, and codeine. Semisynthetic opioids such as oxycodone, hydrocodone, hydromorphone, and oxymorphone may or may not appear in urine drug screens depending on dose and slight structural dissimilarity to morphine, due in part to a lack of a hydroxy group on the common phenanthrene nucleus. 2
Oxycodone generally requires a specific assay for detection and commonly does not show up on a routine opiate immunoassay because it is derived from thebaine, not morphine. 2 Oxycodone has reduced affinity to the antibodies used in most opiate assays. Therefore, in order to be detected on an opiate drug screen, oxycodone requires six times higher urine concentrations than morphine. Some opiate assays have similar rates of detection of morphine and hydrocodone, whereas others require two to three times higher hydrocodone concentrations in order to generate a positive result. 8 The synthetic opioids methadone, fentanyl, tramadol, tapentadol, and buprenorphine have specific assay tests that must be conducted in order to detect the substance.
It is important to understand opioid metabolism in order to make informed decisions regarding interpretation of opioids that may be present in urine drug screens. 9 The flowchart below (Figure 1) explains this process.
Figure 1. Opioid metabolic pathways. Modified from reference 10.
There are several substances that may cause opiate false positives (see Table III). Poppy seeds seldom produce positive results on opiate immunoassays, for instance, as they do not contain morphine in concentrations > 2,000 ng/mL as required for detection. 8 However, 15 grams of poppy seeds in a muffin, 1 teaspoon of poppy seed filling in a cookie, poppy seed bagels, and rolls containing 2 grams of poppy seed have been found to produce detectable amounts of morphine and codeine by immunoassay; however the data remains clinically weak. 5,12-14 One method that may help determine whether poppy seeds are a potential offender is to conduct quantitative testing to determine a morphine:codeine ratio. If the ratio is > 2:1 respectively, poppy seeds or heroin may be present. 8
The cannabinoid immunoassay primarily detects 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid, but also other metabolites of tetrahydrocannabinol. Food products prepared with hemp seeds (eg, hemp flour, hemp-infused alcoholic beverages, hemp seed tea, hemp seed oil, etc.) may produce THC metabolites. However, in most instances, food products do not contain enough THC to produce a positive urine drug screen. 2
One study evaluating hemp seed tea discovered that cannabinoids could be found in the urine after ingestion of 12 to 24 ounces. None of the urine samples met the positive cutoff concentrations for urine drug screens or gas chromatography–mass spectrometry (GC-MS) testing. Several case reports have demonstrated the presence of THC in the urine after hemp seed oil consumption. 5
Pure CBD should not produce a positive result on a cannabinoid screening because it is not metabolized into THC. For instance, 10,000 ng/mL of cannabidiol produced a negative result via a commercial cannabinoid screening product. 15 CBD products must have less than or equal to 0.3% THC by dry weight to be consumed legally, according to the Agriculture Improvement Act of 2018. However, because CBD oil production is not regulated, there may be THC in excess of 0.3% present. 16
Another study analyzing 83 CBD oil products via liquid chromatography (LC) discovered that 21% contained THC. Tetrahydrocannabinol content ranged from 0 to 6.43 mg/mL. 17 Therefore, some of these samples contained 0.64% THC, which is more than double the legal limit. It is at the clinician’s discretion as to what steps may be taken if THC is present in the urine of a patient who is a known user of CBD oil. Further testing of the urine sample and CBD product may be prudent.
NSAIDs may cause THC false positives on UDM. 5 Some studies have suggested that the active metabolite of efavirenz, efavirenz-8-glucuronide, may interact with cannabinoid immunoassays to generate a positive result for THC. 5,11 Proton pump inhibitors have also resulted in THC false positives on urine drug screens. 5 Dronabinol (Marinol) is likely to produce positive results on THC immunoassays because this medication consists of synthetic delta-9-tetrahydrocannabinol (see Table IV). 18
Passive Exposure to Marijuana
There has been much debate regarding whether or not passive exposure to marijuana may lead to a positive urine drug screen result; there is some potential for an individual to have detectable amounts of THC in their system after being exposed to marijuana smoke. However, in most cases, the amount of THC present has not been shown to surpass 50 ng/mL to trigger positive results on UDM.
Additionally, specific conditions must exist in order for this to occur. For example, riding in a vehicle with all of the windows up while other individuals are smoking marijuana. Passive exposure in a more open or ventilated environment is not likely to amount to detectable THC via immunoassay. 2,5
Return to the Patient Case
The patient’s UDM was positive for opiates, oxycodone, and THC. The positive opiate and oxycodone results were expected because the patient takes prescribed oxycodone. Additionally, the patient had an unexpected positive result for THC. (Note that the patient is prescribed pantoprazole for GERD. Proton pump inhibitors may rarely produce false positive results for THC on urine drug screens.) Since a positive result for THC created occupational ramifications for this patient—specifically, losing her job—definitive testing was ordered via GC-MS.
Results of the GC-MS testing came back as follows: pantoprazole, oxymorphone, oxycodone, acetaminophen, and THC. Urine creatinine was 56 mg/dL. Results showed expected prescribed medications as well as their metabolites, and the urine sample was untampered. However, THC was still present. What might a clinician do in this situation?
Laying down ground rules regarding the utilization of non-prescribed and illegal substances during an initial patient encounter is important. Be sure to provide the patient with a written agreement outlining your expectations, UDM requirements, and potential consequences for aberrant behavior or abnormal urine drug screen results.
Use of THC may or may not be allowed in your practice. In examples similar to the presented case, clinicians may consider testing of the CBD oil product to determine whether there is indeed THC content. If THC is not permitted, the clinician may remind the patient that continued use of the substance containing THC could lead to discontinuation of pain medications and/or dismissal from the clinic. If future urine drug screens show positive results for THC, this could be considered a breach of the controlled substance agreement and opioids may be tapered off at that point.
Clinical judgments should always be made on a case-by-case basis. However, the utilization of pain agreements and early discussions with the patient about the clinic rules will help to establish transparency and provide clear directions for the patient to follow.
Care should be taken when interpreting tetrahydrocannabinol and opioid immunoassays as there may be various reasons for a positive or negative result. In relation to THC, CBD oil production and sale is not regulated. Therefore, CBD oil products may contain more than the legal amount of THC content. Finally, understanding opioid metabolism may help prescribing clinicians to properly interpret urine drug monitoring results and to recognize when further screening may be needed.