title: Federal guidelines for marijuana screening should have lower cutoff levels. A comparison of results from immunoassays and gas chromatography-mass spectrometry.
abstract: Federal guidelines for urine marijuana testing use a screening cutoff of 100 ng/mL and a confirming cutoff of 15 ng/mL. We tested 75 urine samples with two different immunoassays with cutoff points of 100 and 20 ng/mL. The same samples were also analyzed with gas chromatography-mass spectrometry. At the government recommended cutoff levels for screening and confirming, test sensitivity was 47% and specificity was 91%. With a screening cutoff of 20 ng/mL confirmed at 5 ng/mL, test sensitivity was 88% and specificity was 94%. We suggest adoption of these lower cutoff levels.
authors.affiliation: Department of Pediatrics, University of Virginia Health Sciences Center, Charlottesville.
authors.forename: D E
authors.initials: DE
authors.lastname: Smith
authors.forename: M E
authors.initials: ME
authors.lastname: Gutgesell
authors.forename: R H
authors.initials: RH
authors.lastname: Schwartz
authors.forename: M M
authors.initials: MM
authors.lastname: Thorne
authors.forename: S
authors.initials: S
authors.lastname: Bogema
mesh_terms: D002849:Chromatography, Gas; D013759:Dronabinol / Q000652:urine*; D006801:Humans; D007124:Immunoenzyme Techniques; D008385:Marijuana Smoking / Q000453:epidemiology / Q000652:urine*; D013058:Mass Spectrometry; D011237:Predictive Value of Tests; D012016:Reference Values; D015813:Substance Abuse Detection / Q000331:legislation & jurisprudence / Q000592:standards*; D014481:United States
chemical_list: D013759:Dronabinol