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Test 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, U

Specimen Type

Urine

Specimen 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

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

Clinical Reference

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

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

Performing 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