Urinary cannabinoid detection times after controlled oral administration of delta9-tetrahydrocannabinol to humans.
BACKGROUND
Urinary cannabinoid excretion and immunoassay performance were evaluated by semiquantitative immunoassay and gas chromatography-mass spectrometry (GC/MS) analysis of metabolite concentrations in 4381 urine specimens collected before, during, and after controlled oral administration of tetrahydrocannabinol (THC).


METHODS
Seven individuals received 0, 0.39, 0.47, 7.5, and 14.8 mg THC/day in this double-blind, placebo-controlled, randomized, clinical study conducted on a closed research ward. THC doses (hemp oils with various THC concentrations and the therapeutic drug Marinol) were administered three times daily for 5 days. All urine voids were collected over the 10-week study and later tested by Emit II, DRI, and CEDIA immunoassays and by GC/MS. Detection rates, detection times, and sensitivities, specificities, and efficiencies of the immunoassays were determined.


RESULTS
At the federally mandated immunoassay cutoff (50 microg/L), mean detection rates were <0.2% during ingestion of the two low doses typical of current hemp oil THC concentrations. The two high doses produced mean detection rates of 23-46% with intermittent positive tests up to 118 h. Maximum metabolite concentrations were 5.4-38.2 microg/L for the low doses and 19.0-436 micro g/L for the high doses. Emit II, DRI, and CEDIA immunoassays had similar performance efficiencies of 92.8%, 95.2%, and 93.9%, respectively, but differed in sensitivity and specificity.


CONCLUSIONS
The use of cannabinoid-containing foodstuffs and cannabinoid-based therapeutics, and continued abuse of oral cannabis require scientific data for accurate interpretation of cannabinoid tests and for making reliable administrative drug-testing policy. At the federally mandated cannabinoid cutoffs, it is possible but unlikely for a urine specimen to test positive after ingestion of manufacturer-recommended doses of low-THC hemp oils. Urine tests have a high likelihood of being positive after Marinol therapy. The Emit II and DRI assays had adequate sensitivity and specificity, but the CEDIA assay failed to detect many true-positive specimens.
Gustafson
Richard A
RA
Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA.
Levine
Barry
B
Stout
Peter R
PR
Klette
Kevin L
KL
George
M P
MP
Moolchan
Eric T
ET
Huestis
Marilyn A
MA
D000284:Administration, Oral; D000328:Adult; D002188:Cannabis; D004311:Double-Blind Method; D013759:Dronabinol / Q000008:administration & dosage / Q000652:urine*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007118:Immunoassay; D008297:Male; D010938:Plant Oils / Q000008:administration & dosage / Q000378:metabolism*; D012016:Reference Values; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods*; D013997:Time Factors
D010938:Plant Oils; D013759:Dronabinol