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Test 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.


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

Specimen Type

Urine

Specimen Minimum Volume

6 mL

Specimen Stability Information

Specimen Type Temperature Time
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.

Clinical Information

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 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.

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.

Day(s) Performed

Monday through Friday

Report Available

2 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

82570

80349

G0480, if appropriate

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.