| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing | |
Marijuana, which is derived from the cannabis plant and contains psychoactive tetrahydrocannabinol (THC) compounds, is the most commonly used federally controlled substance in the United States.1 When abused, marijuana can lead to intoxication, withdrawal, and biopsychosocial issues.2 Since prolonged use can lead to physical dependence and development of cannabis use disorder,3 urine drug testing (UDT) as an evidence-based, therapeutic tool to identify and monitor marijuana use in support of patient recovery is recommeneded.4
Our comprehensive portfolio of marijuana testing includes a unique evaluation that accurately characterizes marijuana through identification of both delta-8 and delta-9 carboxy THC metabolites. This approach is consistent with American Society of Addiction Medicine’s national consensus statement recommending UDT to identify the presence of prescribed and approved medication taken as part of addiction recovery therapy, as well as illicit substances most commonly abused.
Marijuana test menu
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Comprehensive testing to monitor polysubstance use
Understanding which substances patients have ingested improves providers’ abilities to determine the effectiveness of the treatment plan and provide motivation or reinforcement for abstinence. Because we understand that testing needs vary by institution and patient, our marijuana monitoring assays are orderable individually or as part of comprehensive controlled substance or addiction rehabilitation monitoring to identify polysubstance use and to help physicians manage, monitor, and support patient recovery from substance use disorders.
Gold standard testing strategies typically assess for delta-9 carboxy-tetrahydrocannabinol (THC-COOH), the major metabolite of the main psychoactive cannabinoid delta-9 THC, present in urine. However, due to the extended window of detection for THC and the recent emergence of delta-8 THC, another psychoactive cannabinoid synthesized from hemp plants, accurately identifying use and/or cessation presents analytical and medico-legal challenges.8
Key testing
Highlights
Paul Jannetto, Ph.D., and Loralie Langman, Ph.D., discuss Mayo Clinic Laboratories’ new marijuana monitoring evaluation, which identifies metabolites of both delta-9 tetrahydrocannabinol (THC) and delta-8 THC to accurately identify and characterize patients’ marijuana use.
In this episode of “Lab Medicine Rounds,” Justin Kreuter, M.D., sits down with Paul Jannetto, Ph.D., associate professor of laboratory medicine and pathology at Mayo Clinic, and discusses how CBD can affect your health, what the medical benefits are, and its impact on urine drugs of abuse testing.
Since marijuana is lipophilic and has a long elimination half-life, THC and its major metabolite, delta-9 carboxy-tetrahydrocannabinol (THC-COOH), can be detected in urine for weeks to months after the last usage. Traditional laboratory testing often fails to distinguish between new and residual drug use, leading to misinterpretation of positive test results. Because multiple positive urine test results can lead to discharge from a drug treatment program, loss of employment, loss of child custody, and other negative consequences, differentiating between new and past use is critical.
Propelled by research highlighting a better approach to identifying marijuana use, we created a carboxy-THC and creatinine ratio urine test that facilitates the use of decision ratios to determine new versus residual marijuana use.
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Compare decision ratios to confirm THC cessation
Our research-driven assay begins with obtaining two creatinine-normalized carboxy-THC ratios in urine where the collections are 1–7 days apart.
Next, using the creatinine-normalized THC-COOH ratios from the results above, calculate the decision ratio by taking the second creatinine-normalized THC-COOH result (U2) and dividing it by the first creatinine-normalized carboxy-THC (U1). Finally, compare the decision ratio to an interpretation table using the time interval between the two collections. For the most conservative approach to reporting new marijuana usage, compare the U2/U1 decision ratio to see if it was greater than the maximum listed in the table. However, a more realistic decision ratio with reasonable certainty would be to use the 95% below limits in the same table. If the U2/U1 ratios are above these limits, it would indicate new usage between those collection time points.
Key testing
Highlights
In this month's "Hot Topic," Paul Jannetto, Ph.D., identifies how to determine new vs. residual use of marijuana in a patient, and teaches how to calculate the carboxy-tetrahydrocannabinol (carboxy-THC) to creatinine ratio along with a decision ratio by demonstrating its clinical utility via case study.