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HelpTest Code THCCU Delta-9-Carboxy-Tetrahydrocannabinol Confirmation and Creatinine Ratio, Random, Urine
Specimen Required
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.
Useful For
Measuring the delta-9 carboxy-tetrahydrocannabinol (delta-9-THC-COOH) to creatinine ratio as a part of a profile
Method Name
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)
Reporting Name
THC-COOH/Creatinine Ratio, USpecimen Type
UrineSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 14 days | ||
| Ambient | 72 hours |
Reject Due To
| Gross hemolysis | OK |
| Gross icterus | Reject |
Reference Values
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
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 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 |
Day(s) Performed
Monday through Friday
Report Available
3 to 5 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
80349
G0480, if appropriate
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| THCCU | THC-COOH/Creatinine Ratio, U | 19055-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 616334 | Delta-9 Carboxy-Tetrahydrocannabinol by LC-MS/MS | 20521-1 |
| 616335 | Carboxy-THC Interpretation | 69050-3 |
| 616336 | THC-COOH/Creatinine Ratio | 19055-3 |