TY  - JOUR
PY  - 2019//
TI  - Can a threshold for 11-nor-9-carboxy-Δ<sup>9</sup> -tetrahydrocannabinol in hair be derived when its respective concentration in blood serum indicates regular use?
JO  - Drug testing and analysis
A1  - Zinka, B.
A1  - Epple, S.
A1  - Schick, S.
A1  - Skopp, G.
A1  - Graw, M.
A1  - Musshoff, F.
SP  - 325
EP  - 330
VL  - 11
IS  - 2
N2  - 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 analysed 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.<br><br>This article is protected by copyright. All rights reserved.<p />  <p>Language: en</p>
LA  - en
SN  - 1942-7603
UR  - http://dx.doi.org/10.1002/dta.2496
ID  - ref1
ER  -