Can a threshold for 11‐nor‐9‐carboxy‐Δ9 ‐tetrahydrocannabinol in hair be derived when its respective concentration in blood serum indicates regular use?. Issue 2 (11th October 2018)

• Record Type: Journal Article
• Authors: Zinka, Bettina; Epple, Sabine; Schick, Sylvia; Skopp, Gisela; Graw, Matthias; Musshoff, Frank
• Is Part Of: Drug testing and analysis. Volume 11:Issue 2(2019)
• Page Start: 325
• Page End: 330
• Publication Date: 2018-10-11
• Subjects: 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol -- blood -- frequent use -- hair -- threshold; Drugs -- Analysis -- Periodicals; Drug testing -- Periodicals; Chemistry, Forensic -- Periodicals; 615.1901
• DOI: 10.1002/dta.2496
• Languages: English
• ISSNs: 1942-7603

Abstract

Abstract: A 100 μg/L or higher concentration of 11‐nor‐9‐carboxy‐Δ9‐tetrahydrocannabinol (THC‐COOH) in blood serum is generally assumed to be associated with regular and/or heavy use of cannabis. At present, determination of the extent of cannabis use by means of the concentration of THC‐COOH in hair has not been assessed. Therefore, we aimed at establishing a threshold for THC‐COOH concentrations in hair to prove frequent consumption by comparing THC‐COOH concentrations in 129 corresponding serum and hair samples, respectively. The concentration of THC‐COOH in the serum was analyzed by gas chromatography–mass spectrometry and in the hair by liquid chromatography–tandem mass spectrometry. Data were statistically evaluated using receiver operating characteristic curves and contingency tables. Our results suggest that a THC‐COOH concentration of ≥4.2 pg/mg in hair was always accompanied by a THC‐COOH concentration of at least 100 μg/L in blood serum. Should this be confirmed by further studies of a larger study population, a hair concentration of 4.2 pg/mg THC‐COOH can be set as a threshold to predict regular and/or heavy consumption of cannabis even if no corresponding blood sample is available for analysis. Abstract : This study investigated whether a threshold for the THC‐COOH concentration in hair or a specific "blood‐to‐hair coefficient" could be established to prove frequent consumption of cannabis products, such as hashish or marihuana.