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THCCOOH concentrations in whole blood: Are they useful in discriminating occasional from heavy smokers?
Author(s) -
Fabritius Marie,
Favrat Bernard,
Chtioui Haithem,
Battistella Giovanni,
Ani JeanMarie,
Appenzeller Monique,
Dao Kim,
Fornari Eleonora,
Lauer Estelle,
Mall JeanFrédéric,
Maeder Philippe,
Mangin Patrice,
Staub Christian,
Giroud Christian
Publication year - 2013
Publication title -
drug testing and analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.065
H-Index - 54
eISSN - 1942-7611
pISSN - 1942-7603
DOI - 10.1002/dta.1581
Subject(s) - cannabis , driving under the influence , dronabinol , abstinence , forensic toxicology , drugs of abuse , poison control , medicine , cannabinol , tetrahydrocannabinol , cannabinoid , injury prevention , emergency medicine , drug , chemistry , pharmacology , chromatography , cannabidiol , psychiatry , receptor
Some forensic and clinical circumstances require knowledge of the frequency of drug use. Care of the patient, administrative, and legal consequences will be different if the subject is a regular or an occasional cannabis smoker. To this end, 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (THCCOOH) has been proposed as a criterion to help to distinguish between these two groups of users. However, to date this indicator has not been adequately assessed under experimental conditions. We carried out a controlled administration study of smoked cannabis with a placebo. Cannabinoid levels were determined in whole blood using tandem mass spectrometry. Significantly high differences in THCCOOH concentrations were found between the two groups when measured during the screening visit, prior to the smoking session, and throughout the day of the experiment. Receiver operating characteristic (ROC) curves were determined and two threshold criteria were proposed in order to distinguish between these groups: a free THCCOOH concentration below 3 µg/L suggested an occasional consumption (≤ 1 joint/week) while a concentration higher than 40 µg/L corresponded to a heavy use (≥ 10 joints/month). These thresholds were tested and found to be consistent with previously published experimental data. The decision threshold of 40 µg/L could be a cut‐off for possible disqualification for driving while under the influence of cannabis. A further medical assessment and follow‐up would be necessary for the reissuing of a driving license once abstinence from cannabis has been demonstrated. A THCCOOH level below 3 µg/L would indicate that no medical assessment is required. Copyright © 2013 John Wiley & Sons, Ltd.