THC
Label Mnemonic: THCR
Epic Lab Code: LAB7388
Downtime Form: A-1a Miscellaneous Request
Chemistry
6240 RCP
356-3527
Specimen(s):
Urine Screen + Reflexed Confirmation, Random
Collection Medium:
Clear top tube
Alternate Collection Media:
Urine (Random)-BD Vacutainer®, no additive yellow top
Minimum:
5 mL random urine
Rejection Criteria:
Test cannot be added to a urine sample previously utilized for urinalysis testing (LAB1160, LAB1164, LAB8379).
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
1 hour (upon receipt in laboratory)
Reference Range:
None
Comments:
Screen includes THC with a cutoff of 50 ng/mL for the main metabolite of THC (9-carboxy-THC). All positive screening tests are automatically reflexed to a mail-out confirmation assay that uses liquid chromatography-tandem mass spectrometry (LC/MS/MS) to provide definitive identification and quantitation of 9-carboxy-THC. It is highly unlikely that passive (second-hand) inhalation of marijuana smoke will result in a positive screening test. Research studies have shown that maximum urinary concentrations of 9-carboxy- THC levels only reach 15-20 ng/mL following passive inhalation of heavy marijuana smoke. References: Cone EJ, Johnson RE, Darwin WD, Yousefnejad D, Mell LD, Paul BD, Mitchell J. Passive inhalation of marijuana smoke: urinarlysis and room air levels of delta-9-tetrahydrocannabinol. J Anal Toxicol 1987;11:89-96. Hammett-Stabler CA, Pesce AJ, Cannon DJ. Urine Drug Screening in the Medical Setting. Clinica Chimica Acta 2002;315:125-135.
Test Limitations:
There is the possibility that other substances and/or factors may interfere with the test and cause erroneous results (e.g., technical or procedural errors). Call the lab at 319-356-3527 for additional information.
Methodology:
Assay is based on the kinetic interaction of microparticles in a solution (KIMS) as measured by changes in light transmission.
CPT Code:
80349
 
See also:
Drugs of Abuse, Urine
Drugs of Abuse, Urine + Confirm
THC, Urine Screen, Random