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HelpTest Code THCCR Delta 9-Carboxy-Tetrahydrocannabinol (THC-COOH) Confirmation and Creatinine Ratio, Random, Urine
Specimen Required
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. Submit 10 mL in a plastic container.
3. No preservative.
Additional Information:
1. No specimen substitutions.
2. Submitting less than 10 mL may compromise the ability to perform all necessary testing.
3. STAT requests are not accepted for this test.
Useful For
Measuring the delta-9 carboxy-tetrahydrocannabinol to creatinine ratio to detect use of tetrahydrocannabinol
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| THCCU | THC-COOH/Creatinine Ratio, U | No | Yes |
| CRETR | Creatinine, Random, U | No | Yes |
Method Name
THCCU: Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
CRETR: Enzymatic Colorimetric Assay
Reporting Name
THC-COOH/Creatinine Ratio, USpecimen Type
UrineSpecimen Minimum Volume
6 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days | ||
| Ambient | 72 hours |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Reference Values
Carboxy-Tetrahydrocannabinol (THC):
Not Detected
Cutoff concentration:
Delta-9 Carboxy-tetrahydrocannabinol by liquid chromatography tandem mass spectrometry: <5.0 ng/mL
Creatinine:
≥18 years old: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years.
Interpretation
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 the Table. 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. 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 |
Day(s) Performed
Monday through Friday
Report Available
2 to 4 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
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.CPT Code Information
82570
80349
G0480, if appropriate
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| THCCR | THC-COOH/Creatinine Ratio, U | 19055-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CRETR | Creatinine, Random, U | 2161-8 |
| 616334 | Delta-9 Carboxy-Tetrahydrocannabinol by LC-MS/MS | 20521-1 |
| 616335 | Carboxy-THC Interpretation | 69050-3 |
| 616336 | THC-COOH/Creatinine Ratio | 19055-3 |
Forms
If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.