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Test Code THCU Carboxy-Tetrahydrocannabinol (THC) Confirmation, Random, Urine

Additional Codes


Powerchart: THC (Cannabis) Confirmation GC/MS Urine

MA Cerner: Urine Carboxy-Tetrahydrocannabinol Confirmation

Reporting Name

Carboxy-THC Confirmation, U

Useful For

Confirmation of drug abuse involving delta-9-tetrahydrocannabinol (marijuana)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Ordering Guidance

1. For situations where chain of custody is required, a Chain-of-Custody Kit (T282) is available. For chain-of-custody testing, order THCX / Carboxy-Tetrahydrocannabinol (THC) Confirmation, Chain of Custody, Random, Urine.

2. Additional drug panels and specific requests are available. Call 800-533-1710 or 507-266-5700.

3. If urine creatinine is required or adulteration of the sample is suspected, order, ADULT / Adulterants Survey, 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. No preservative.

Additional Information:

1. No specimen substitutions.

2. STATS are not accepted for this test.

Specimen Minimum Volume

5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Reference Values



Cutoff concentration:

Carboxy-THC- by GC/MS <3.0 ng/mL

Day(s) Performed

Monday through Friday

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


G0480 (if appropriate)

MercyOne Laboratory Test Catalog Note:

If Medicare, G0480 is covered under a medical necessity rule; obtain an ABN.

LOINC Code Information

Test ID Test Order Name Order LOINC Value
THCU Carboxy-THC Confirmation, U 20521-1


Result ID Test Result Name Result LOINC Value
2497 Carboxy-THC- by GC/MS 20521-1
21186 Carboxy-THC Interpretation 69050-3
21187 Chain of Custody 77202-0

Report Available

3 to 5 days

Reject Due To

Gross hemolysis OK
Gross icterus OK

Method Name

Gas Chromatography-Mass Spectrometry (GC-MS) Confirmation with Quantitation


If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Therapeutics Test Request (T831)