Test ID: THCU
Tetrahydrocannabinol (THC) Confirmation, Urine
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
Detection and confirmation of drug abuse involving delta-9-tetrahydrocannabinol (marijuana)
Additional Tests Lists test(s) that are always performed, at an additional charge, with the initial test(s)
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| ADULT | Adulterants Survey, U | No | Yes |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
An evaluation to detect the presence of adulterants will be performed and reported at no additional charge.
See Adulterant Survey Algorithm in Special Instructions.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
THCU/8898: Immunoassay/Gas Chromatography-Mass Spectrometry (GC-MS) Confirmation with Quantitation
ADULT/29345: Spectrophotometry (SP)
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
J (Jane) (Tetrahydrocannabinol)
Jane (Tetrahydrocannabinol)
Marijuana (Tetrahydrocannabinol)
Mary Jane (Tetrahydrocannabinol)
Tetrahydrocannabinol (THC) Confirmation, Quantitative, Urine
TETRAHYDROCANNABINOL, QN
THC (Tetrahydrocannabinol)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Container/Tube: Plastic, 60-mL urine bottle
Specimen Volume: 20 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Additional Information:
1. No specimen substitutions.
2. No STATS are accepted for this procedure.
3. For situations where chain-of-custody is required, a Chain-of-Custody Kit (Supply T282) is available. For chain-of-custody information, see COCH/9426 Chain-of-Custody Processing.
4. Additional drug panels and specific requests are available. Call Mayo Medical Laboratories at 800-533-1710 or 507-266-5700.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 14 days |
| Frozen | 14 days | |
| Ambient | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Delta-9-tetrahydrocannabinol is the active agent of the popularly abused street drug, marijuana.
Following consumption of the drug, either by inhalation or ingestion, it is metabolized to a variety of inactive chemicals, 1 of them being delta-9-tetrahydrocannabinol carboxylic acid.
The immunochemical procedure used to screen for tetrahydrocannabinol (THC) as part of #8248 "Drug Abuse Survey, Urine" is designed to cross-react with THC carboxylic acid.
In almost all medico-legal cases and in screening of employees, or when the patient adamantly denies THC use and the immunochemical test is positive, confirmation of the result by gas chromatography-mass spectrometry (GC-MS) and EIA are required.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Negative
Positives are reported with a quantitative GC-MS result.
Cutoff concentrations:
IMMUNOASSAY SCREEN
<20 ng/mL
THC CARBOXYLIC ACID BY GC-MS
<3 ng/mL
Interpretation Provides information to assist in interpretation of the test results
The presence of tetrahydrocannabinol carboxylic acid (THC-COOH), a major metabolite of delta-9-tetrahydrocannabinol, in urine at concentrations >15 ng/mL is a strong indicator that the patient has used marijuana.
The metabolite of marijuana (THC-COOH) has a long half-life and can be detected in urine for more than 7 days after a single use. The presence of THC-COOH in urine >100 ng/mL indicates relatively recent use, probably within the past 7 days. Levels >500 ng/mL suggest chronic and recent use. Chronic use causes accumulation of THC and THC-COOH in adipose tissue such that it is excreted into the urine for as long as 30 to 60 days from the time chronic use is halted.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
No significant cautionary statements
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Moyer TP, Palmen MA, Johnson P, et al: Marijuana testing-how good is it? Mayo Clin Proc 1987;62:413-417
Method Description Describes how the test is performed and provides a method-specific reference
The gas chromatography-mass spectrometry procedure yields quantitative results by a different technique than the immunochemical procedure, and serves primarily as a documentary procedure when results of the immunochemical procedure used in #8248 "Drug Abuse Survey, Urine" come into question. (Moyer TP, Palmen MA, Johnson P, et al: Marijuana testing-how good is it? Mayo Clin Proc 1987;62:413-417)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
80299
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| 2449 | Immunoassay Screen | 19415-9 |
| 2497 | THC Carboxylic Acid-by GC/MS | 3530-3 |
| 21186 | Interpretation | 69050-3 |
| 21187 | Chain of Custody | In Process |
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