Measuring the delta-9 carboxy-tetrahydrocannabinol (delta-9-THC-COOH) to creatinine ratio as a part of a profile
Only orderable as part of a profile. For more information see THCCR / Delta 9-Carboxy-Tetrahydrocannabinol (THC-COOH) Confirmation and Creatinine Ratio, Random, Urine
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Cannabinoids (Tetrahydrocannabinol)
J (Jane) (Tetrahydrocannabinol)
Jane (Tetrahydrocannabinol)
Marijuana (Tetrahydrocannabinol)
Mary Jane (Tetrahydrocannabinol)
Tetrahydrocannabinol (THC) Confirmation, Quantitative, Urine
TETRAHYDROCANNABINOL, QN
THC (Tetrahydrocannabinol)
Urine
Only orderable as part of a profile. For more information see THCCR / Delta 9-Carboxy-Tetrahydrocannabinol (THC-COOH) Confirmation and Creatinine Ratio, Random, Urine
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container Tube: Plastic urine container
Submission Container/Tube: Plastic, 5-mL tube
Specimen Volume: 3 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Additional Information:
1. No specimen substitutions.
2. STAT requests are not accepted for this test.
0.5 mL
Gross hemolysis | OK |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 14 days | ||
Ambient | 72 hours |
Measuring the delta-9 carboxy-tetrahydrocannabinol (delta-9-THC-COOH) to creatinine ratio as a part of a profile
Delta-9-tetrahydrocannabinol (THC) is the active agent of the popularly abused/used drug, cannabis/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 (delta-9-THC-COOH).
For confirmation of abstinence, urine analysis is a useful tool. The presence of delta-9-THC-COOH is a strong indicator that a patient has used cannabis/marijuana. However, increases in urine delta-9-THC-COOH concentrations resulting from changes in urinary output may be mistakenly interpreted as new drug use rather than carryover from previous drug exposure. Individuals continue to excrete THC-COOH for days after abstinence, and although concentrations generally decrease with time, the concentrations can fluctuate with levels of hydration. As a result, the division of urinary delta-9-THC-COOH concentrations by creatinine produces a metabolite/creatinine ratio that should decrease until a new episode of drug use occurs. Delta-9-THC-COOH/creatinine ratios of specimens collected over time can be compared to determine if new cannabis/marijuana use has occurred.
Only orderable as part of a profile. For more information see THCCR / Delta 9-Carboxy-Tetrahydrocannabinol (THC-COOH) Confirmation and Creatinine Ratio, Random, Urine
Not detected
Cutoff concentration:
<5.0 ng/mL
Delta-9 carboxy-tetrahydrocannabinol (delta-9-THC-COOH) and creatinine concentrations must be obtained for at least 2 urine specimens with a known time interval (1-7 days) between collections. Using these creatinine-normalized delta-9-THC-COOH concentrations, a ratio is calculated between the concentration of any urine specimen (U2) divided by the concentration in a previously collected urine specimen (U1). The most conservative method for reporting new cannabis/marijuana use between collections would apply a U2/U1 decision ratio equal to the maxima listed in Table 1. A more realistic decision ratio with reasonable certainty would be to use the 95% below limits in the same table. U2/U1 ratios above these limits would indicate new usage between those collection time points.
Table 1. Adapted from Smith ML et al. for less than daily users of cannabis/marijuana.(1)
Time interval between urine collections (hours) | Maximum ratio (U2/U1) | 95% Below (U2/U1) |
0-23.9 | 6.29 | 1.42 |
24-47.9 | 2.27 | 1.01 |
48-71.9 | 1.47 | 0.853 |
72-95.9 | 1.63 | 0.595 |
96-119.9 | 0.555 | 0.347 |
120-143.9 | 0.197 | 0.146 |
144-167.9 | 0.080 | 0.073 |
No significant cautionary statements
1. Smith ML, Barnes AJ, Huestis MA. Identifying new cannabis use with urine creatinine normalized THCCOOH concentrations and time intervals between specimen collections. J Anal Toxicol. 2009;33(4):185-189. doi:10.1093/jat/33.4.185
2. Huestis MA, Cone EJ. Differentiating new marijuana use from residual drug excretion in occasional marijuana users. J Anal Toxicol. 1998;22(6):445-454. doi:10.1093/jat/22.6.445
3. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 43
This test includes immunoassay and confirmation with quantification by liquid chromatography tandem mass spectrometry.(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. It 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 |
---|---|---|
THCCU | THC-COOH/Creatinine Ratio, U | 19055-3 |
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.
|
---|---|---|
616334 | Delta-9 Carboxy-Tetrahydrocannabinol by LC-MS/MS | 20521-1 |
616335 | Carboxy-THC Interpretation | 69050-3 |
616336 | THC-COOH/Creatinine Ratio | 19055-3 |