Confirmation of drug abuse involving delta-9-tetrahydrocannabinol (marijuana)
Gas Chromatography-Mass Spectrometry (GC-MS) Confirmation with Quantitation
Cannabinoids (Tetrahydrocannabinol)
J (Jane) (Tetrahydrocannabinol)
Jane (Tetrahydrocannabinol)
Marijuana (Tetrahydrocannabinol)
Mary Jane (Tetrahydrocannabinol)
Tetrahydrocannabinol (THC) Confirmation, Quantitative, Urine
TETRAHYDROCANNABINOL, QN
THC (Tetrahydrocannabinol)
Urine
1. For situations where chain of custody is required, a Chain-of-Custody Kit (T282) is available. For chain-of-custody testing, order THCX / Carboxy-Tetrahydrocannabinol (THC) Confirmation, Chain of Custody, Random, Urine.
2. Additional drug panels and specific requests are available. Call 800-533-1710 or 507-266-5700.
3. If urine creatinine is required or adulteration of the sample is suspected, order, ADULT / Adulterants Survey, Random, Urine.
Supplies: Urine Tubes, 10 mL (T068)
Collection Container Tube: Plastic urine container
Submission Container/Tube: 10 mL tube
Specimen Volume: 10 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Additional Information:
1. No specimen substitutions.
2. STATS are not accepted for this test.
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
-General Request (T239)
-Therapeutics Test Request (T831)
5 mL
Gross hemolysis | OK |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 14 days | ||
Ambient | 72 hours |
Confirmation of drug abuse involving delta-9-tetrahydrocannabinol (marijuana)
Delta-9-tetrahydrocannabinol (THC) is the active agent of the popularly abused street drug, marijuana.
Following consumption of the drug, either by inhalation or ingestion, it is metabolized to a variety of inactive chemicals, one of them being delta-9-tetrahydrocannabinol carboxylic acid.
In almost all medico-legal cases and in screening of employees, or when the patient adamantly denies THC use and the immunoassay test is positive, confirmation of the result by gas chromatography-mass spectrometry (GC-MS) is required.
Negative
Cutoff concentration:
Carboxy-THC- by GC/MS <3.0 ng/mL
The presence of tetrahydrocannabinol carboxylic acid (THC-COOH), a major metabolite of delta-9-tetrahydrocannabinol, in urine at concentrations greater than 15.0 ng/mL is a strong indicator that the patient has used marijuana.
The metabolite of marijuana (THC-COOH) has a long half-life and can be detected in urine for more than 7 days after a single use. The presence of THC-COOH in urine greater than 100.0 ng/mL indicates relatively recent use, probably within the past 7 days. Levels greater than 500.0 ng/mL suggest chronic and recent use. Chronic use causes accumulation of THC and THC-COOH in adipose tissue such that it is excreted into the urine for as long as 30 to 60 days from the time chronic use is halted.
No significant cautionary statements
1. Disposition of Toxic Drugs and Chemicals in Man. Tenth edition. Edited by RC Baselt. Biomedical Publications, 2014
2. Langman LJ Bechtel LK, Meier BM, Holstege C: Chapter 41: Clinical Toxicology. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Edited by N Rifai, AR Horvath, CT Wittwer. Sixth edition. Elsevier, 2018, pp 832-887
This test includes immunoassay and confirmation with quantification by gas chromatography-mass spectrometry (GC-MS).(Unpublished Mayo method)
Monday through Friday
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
80349
G0480 (if appropriate)
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
THCU | Carboxy-THC Confirmation, U | 20521-1 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
2497 | Carboxy-THC- by GC/MS | 20521-1 |
21186 | Carboxy-THC Interpretation | 69050-3 |
21187 | Chain of Custody | 77202-0 |