{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,16]],"date-time":"2026-10-16T22:50:21Z","timestamp":1792191021868,"version":"4.4.0"},"reference-count":40,"publisher":"Oxford University Press (OUP)","issue":"2","license":[{"start":{"date-parts":[[2017,2,1]],"date-time":"2017-02-01T00:00:00Z","timestamp":1485907200000},"content-version":"vor","delay-in-days":366,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/100000026","name":"National Institute on Drug Abuse","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000026","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"NIH","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100013161","name":"Office of National Drug Control Policy","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100013161","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100008760","name":"National Highway Traffic Safety Administration","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100008760","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2016,2,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>BACKGROUND<\/jats:title>\n                    <jats:p>In driving-under-the-influence cases, blood typically is collected approximately 1.5\u20134 h after an incident, with unknown last intake time. This complicates blood \u03949-tetrahydrocannabinol (THC) interpretation, owing to rapidly decreasing concentrations immediately after inhalation. We evaluated how decreases in blood THC concentration before collection may affect interpretation of toxicological results.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>METHODS<\/jats:title>\n                    <jats:p>Adult cannabis smokers (\u22651\u00d7\/3 months, \u22643 days\/week) drank placebo or low-dose alcohol (approximately 0.065% peak breath alcohol concentration) 10 min before inhaling 500 mg placebo, 2.9%, or 6.7% vaporized THC (within-individuals), then took simulated drives 0.5\u20131.3 h postdose. Blood THC concentrations were determined before and up to 8.3 h postdose (limit of quantification 1 \u03bcg\/L).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>RESULTS<\/jats:title>\n                    <jats:p>In 18 participants, observed Cmax (at 0.17 h) for active (2.9 or 6.7% THC) cannabis were [median (range)] 38.2 \u03bcg\/L (11.4\u2013137) without alcohol and 47.9 \u03bcg\/L (13.0\u2013210) with alcohol. THC Cmax concentration decreased 73.5% (3.3%\u201389.5%) without alcohol and 75.1% (11.5%\u201385.4%) with alcohol in the first half-hour after active cannabis and 90.3% (76.1%\u2013100%) and 91.3% (53.8%\u201397.0%), respectively, by 1.4 h postdose. When residual THC (from previous self-administration) was present, concentrations rapidly decreased to preinhalation baselines and fluctuated around them. During-drive THC concentrations previously associated with impairment (\u22658.2 \u03bcg\/L) decreased to median &amp;lt;5 \u03bcg\/L by 3.3 h postdose and &amp;lt;2 \u03bcg\/L by 4.8 h postdose; only 1 participant had THC \u22655 \u03bcg\/L after 3.3 h.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>CONCLUSIONS<\/jats:title>\n                    <jats:p>Forensic blood THC concentrations may be lower than common per se cutoffs despite greatly exceeding them while driving. Concentrations during driving cannot be back-extrapolated because of unknown time after intake and interindividual variability in rates of decrease.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1373\/clinchem.2015.248492","type":"journal-article","created":{"date-parts":[[2016,1,28]],"date-time":"2016-01-28T12:22:52Z","timestamp":1453983772000},"page":"367-377","source":"Crossref","is-referenced-by-count":57,"title":["Effect of Blood Collection Time on Measured \u03949-Tetrahydrocannabinol Concentrations: Implications for Driving Interpretation and Drug Policy"],"prefix":"10.1093","volume":"62","author":[{"given":"Rebecca L","family":"Hartman","sequence":"first","affiliation":[{"name":"Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Timothy L","family":"Brown","sequence":"first","affiliation":[{"name":"National Advanced Driving Simulator, University of Iowa, Iowa City, IA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gary","family":"Milavetz","sequence":"first","affiliation":[{"name":"College of Pharmacy, University of Iowa, Iowa City, IA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Spurgin","sequence":"first","affiliation":[{"name":"College of Pharmacy, University of Iowa, Iowa City, IA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David A","family":"Gorelick","sequence":"first","affiliation":[{"name":"Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD"},{"name":"Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gary R","family":"Gaffney","sequence":"first","affiliation":[{"name":"Carver College of Medicine, University of Iowa, Iowa City, IA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marilyn A","family":"Huestis","sequence":"first","affiliation":[{"name":"Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2016,2,1]]},"reference":[{"key":"2020030521300951800_B1","article-title":"Results of the 2013\u20132014 National Roadside Survey of Alcohol and Drug Use by Drivers. 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