11-OH-THC in hair as marker of active cannabis consumption: Estimating a reliable cut-off by evaluation of 672 THC-positive hair samples

Sara Casati, Ilaria Angeli, Alessandro Ravelli, Massimo Del Fabbro, Mauro Minoli, Marica Orioli

Research output: Contribution to journalArticle

Abstract

Hair analysis for the assessment of cannabis active use from passive consumption may be failed when performed by the sole detection of compounds present in plant material as well as in cannabis smoke like Δ‐9‐tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). For this reason, the determination of 11‐nor‐9‐carboxy‐Δ-9-tetrahydrocannabinol (THC‐COOH) has been proposed by the Society of Hair Testing (SoHT) in order to prove active cannabis consumption. The identification of THC-COOH in hair will continue to be complicated by its acidic nature and the critical low concentration due to the preferential incorporation of basic compounds into hair shaft. Alternatively, 11-OH-THC may be considered as a complementary marker for THC administration. Our recent study reported an accurate validated procedure for THC, CBD, CBN and 11-OH-THC in hair, based on a GC/MS-MS method in electron ionization mode. However, unlike THC-COOH, a cut-off level for 11-OH-THC in hair has not been fixed yet. For this reason, the aim of this study is to propose a concentration value for 11-OH-THC in hair analysis in order to discriminate between chronic use and external contamination. Receiver operating characteristics (ROC) analysis was applied for cut‐off evaluation after 11-OH-THC quantification in a pool of 672 THC-positive hair samples. Results have shown a concentration range between 0.01–5.34 ng/mg for THC (mean 0.34 ng/mg, median 0.12), 0.00–19.2 pg/mg for THC-COOH (mean 0.72 pg/mg, median 0.19 pg/mg) and 0.01–13.33 ng/mg for 11-OH-THC (mean 1.09 ng/mg, median 0.51 ng/mg) for scalp hair and between 0.03–6.32 ng/mg for THC (mean 0.82 ng/mg, median 0.30), 0.00–42.1 pg/mg for THC-COOH (mean 2.70 pg/mg, median 1.08 pg/mg) and 0.00–7.88 ng/mg for 11-OH-THC (mean 1.70 ng/mg, median 0.89 ng/mg) for body hair. Considering these experimental data collected in our laboratory, we propose a cut-off level of 0.5 for scalp and body hair, as indicative of cannabis active consumption. The ROC curve AUCs for 11-OH-THC were 0.873 and 0.884 in 590 scalp hair and 82 body hair samples, respectively. The comparison of the results for THC-COOH (control method) and 11-OH-THC (test method) was also made by means of the Cohen's kappa statistics providing a good agreement according to both Landis & Koch and Fleiss scales. Additionally, we suggest that the detection of both THC-COOH and 11-OH-THC should be mandatory in order to prove active intake and exclude false positive results from external contamination.

Original languageEnglish
Article number109951
JournalForensic Science International
Volume304
DOIs
Publication statusPublished - Nov 1 2019

Fingerprint

Dronabinol
Cannabis
hydroxide ion
Cannabinol
Scalp
Cannabidiol
ROC Curve

Keywords

  • 11-Hydroxy-Δ-9-tetrahydrocannabinol
  • Cannabis active use
  • Cut-Off
  • GC–MS/MS
  • Hair
  • Metabolites of Δ–9–tetrahydrocannabinol

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

Cite this

11-OH-THC in hair as marker of active cannabis consumption : Estimating a reliable cut-off by evaluation of 672 THC-positive hair samples. / Casati, Sara; Angeli, Ilaria; Ravelli, Alessandro; Del Fabbro, Massimo; Minoli, Mauro; Orioli, Marica.

In: Forensic Science International, Vol. 304, 109951, 01.11.2019.

Research output: Contribution to journalArticle

@article{efb9a307bbdb4a64ad9ab47c426a31d5,
title = "11-OH-THC in hair as marker of active cannabis consumption: Estimating a reliable cut-off by evaluation of 672 THC-positive hair samples",
abstract = "Hair analysis for the assessment of cannabis active use from passive consumption may be failed when performed by the sole detection of compounds present in plant material as well as in cannabis smoke like Δ‐9‐tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). For this reason, the determination of 11‐nor‐9‐carboxy‐Δ-9-tetrahydrocannabinol (THC‐COOH) has been proposed by the Society of Hair Testing (SoHT) in order to prove active cannabis consumption. The identification of THC-COOH in hair will continue to be complicated by its acidic nature and the critical low concentration due to the preferential incorporation of basic compounds into hair shaft. Alternatively, 11-OH-THC may be considered as a complementary marker for THC administration. Our recent study reported an accurate validated procedure for THC, CBD, CBN and 11-OH-THC in hair, based on a GC/MS-MS method in electron ionization mode. However, unlike THC-COOH, a cut-off level for 11-OH-THC in hair has not been fixed yet. For this reason, the aim of this study is to propose a concentration value for 11-OH-THC in hair analysis in order to discriminate between chronic use and external contamination. Receiver operating characteristics (ROC) analysis was applied for cut‐off evaluation after 11-OH-THC quantification in a pool of 672 THC-positive hair samples. Results have shown a concentration range between 0.01–5.34 ng/mg for THC (mean 0.34 ng/mg, median 0.12), 0.00–19.2 pg/mg for THC-COOH (mean 0.72 pg/mg, median 0.19 pg/mg) and 0.01–13.33 ng/mg for 11-OH-THC (mean 1.09 ng/mg, median 0.51 ng/mg) for scalp hair and between 0.03–6.32 ng/mg for THC (mean 0.82 ng/mg, median 0.30), 0.00–42.1 pg/mg for THC-COOH (mean 2.70 pg/mg, median 1.08 pg/mg) and 0.00–7.88 ng/mg for 11-OH-THC (mean 1.70 ng/mg, median 0.89 ng/mg) for body hair. Considering these experimental data collected in our laboratory, we propose a cut-off level of 0.5 for scalp and body hair, as indicative of cannabis active consumption. The ROC curve AUCs for 11-OH-THC were 0.873 and 0.884 in 590 scalp hair and 82 body hair samples, respectively. The comparison of the results for THC-COOH (control method) and 11-OH-THC (test method) was also made by means of the Cohen's kappa statistics providing a good agreement according to both Landis & Koch and Fleiss scales. Additionally, we suggest that the detection of both THC-COOH and 11-OH-THC should be mandatory in order to prove active intake and exclude false positive results from external contamination.",
keywords = "11-Hydroxy-Δ-9-tetrahydrocannabinol, Cannabis active use, Cut-Off, GC–MS/MS, Hair, Metabolites of Δ–9–tetrahydrocannabinol",
author = "Sara Casati and Ilaria Angeli and Alessandro Ravelli and {Del Fabbro}, Massimo and Mauro Minoli and Marica Orioli",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.forsciint.2019.109951",
language = "English",
volume = "304",
journal = "Forensic Science International",
issn = "0379-0738",
publisher = "Elsevier Ireland Ltd",

}

TY - JOUR

T1 - 11-OH-THC in hair as marker of active cannabis consumption

T2 - Estimating a reliable cut-off by evaluation of 672 THC-positive hair samples

AU - Casati, Sara

AU - Angeli, Ilaria

AU - Ravelli, Alessandro

AU - Del Fabbro, Massimo

AU - Minoli, Mauro

AU - Orioli, Marica

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Hair analysis for the assessment of cannabis active use from passive consumption may be failed when performed by the sole detection of compounds present in plant material as well as in cannabis smoke like Δ‐9‐tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). For this reason, the determination of 11‐nor‐9‐carboxy‐Δ-9-tetrahydrocannabinol (THC‐COOH) has been proposed by the Society of Hair Testing (SoHT) in order to prove active cannabis consumption. The identification of THC-COOH in hair will continue to be complicated by its acidic nature and the critical low concentration due to the preferential incorporation of basic compounds into hair shaft. Alternatively, 11-OH-THC may be considered as a complementary marker for THC administration. Our recent study reported an accurate validated procedure for THC, CBD, CBN and 11-OH-THC in hair, based on a GC/MS-MS method in electron ionization mode. However, unlike THC-COOH, a cut-off level for 11-OH-THC in hair has not been fixed yet. For this reason, the aim of this study is to propose a concentration value for 11-OH-THC in hair analysis in order to discriminate between chronic use and external contamination. Receiver operating characteristics (ROC) analysis was applied for cut‐off evaluation after 11-OH-THC quantification in a pool of 672 THC-positive hair samples. Results have shown a concentration range between 0.01–5.34 ng/mg for THC (mean 0.34 ng/mg, median 0.12), 0.00–19.2 pg/mg for THC-COOH (mean 0.72 pg/mg, median 0.19 pg/mg) and 0.01–13.33 ng/mg for 11-OH-THC (mean 1.09 ng/mg, median 0.51 ng/mg) for scalp hair and between 0.03–6.32 ng/mg for THC (mean 0.82 ng/mg, median 0.30), 0.00–42.1 pg/mg for THC-COOH (mean 2.70 pg/mg, median 1.08 pg/mg) and 0.00–7.88 ng/mg for 11-OH-THC (mean 1.70 ng/mg, median 0.89 ng/mg) for body hair. Considering these experimental data collected in our laboratory, we propose a cut-off level of 0.5 for scalp and body hair, as indicative of cannabis active consumption. The ROC curve AUCs for 11-OH-THC were 0.873 and 0.884 in 590 scalp hair and 82 body hair samples, respectively. The comparison of the results for THC-COOH (control method) and 11-OH-THC (test method) was also made by means of the Cohen's kappa statistics providing a good agreement according to both Landis & Koch and Fleiss scales. Additionally, we suggest that the detection of both THC-COOH and 11-OH-THC should be mandatory in order to prove active intake and exclude false positive results from external contamination.

AB - Hair analysis for the assessment of cannabis active use from passive consumption may be failed when performed by the sole detection of compounds present in plant material as well as in cannabis smoke like Δ‐9‐tetrahydrocannabinol (THC), cannabidiol (CBD), and cannabinol (CBN). For this reason, the determination of 11‐nor‐9‐carboxy‐Δ-9-tetrahydrocannabinol (THC‐COOH) has been proposed by the Society of Hair Testing (SoHT) in order to prove active cannabis consumption. The identification of THC-COOH in hair will continue to be complicated by its acidic nature and the critical low concentration due to the preferential incorporation of basic compounds into hair shaft. Alternatively, 11-OH-THC may be considered as a complementary marker for THC administration. Our recent study reported an accurate validated procedure for THC, CBD, CBN and 11-OH-THC in hair, based on a GC/MS-MS method in electron ionization mode. However, unlike THC-COOH, a cut-off level for 11-OH-THC in hair has not been fixed yet. For this reason, the aim of this study is to propose a concentration value for 11-OH-THC in hair analysis in order to discriminate between chronic use and external contamination. Receiver operating characteristics (ROC) analysis was applied for cut‐off evaluation after 11-OH-THC quantification in a pool of 672 THC-positive hair samples. Results have shown a concentration range between 0.01–5.34 ng/mg for THC (mean 0.34 ng/mg, median 0.12), 0.00–19.2 pg/mg for THC-COOH (mean 0.72 pg/mg, median 0.19 pg/mg) and 0.01–13.33 ng/mg for 11-OH-THC (mean 1.09 ng/mg, median 0.51 ng/mg) for scalp hair and between 0.03–6.32 ng/mg for THC (mean 0.82 ng/mg, median 0.30), 0.00–42.1 pg/mg for THC-COOH (mean 2.70 pg/mg, median 1.08 pg/mg) and 0.00–7.88 ng/mg for 11-OH-THC (mean 1.70 ng/mg, median 0.89 ng/mg) for body hair. Considering these experimental data collected in our laboratory, we propose a cut-off level of 0.5 for scalp and body hair, as indicative of cannabis active consumption. The ROC curve AUCs for 11-OH-THC were 0.873 and 0.884 in 590 scalp hair and 82 body hair samples, respectively. The comparison of the results for THC-COOH (control method) and 11-OH-THC (test method) was also made by means of the Cohen's kappa statistics providing a good agreement according to both Landis & Koch and Fleiss scales. Additionally, we suggest that the detection of both THC-COOH and 11-OH-THC should be mandatory in order to prove active intake and exclude false positive results from external contamination.

KW - 11-Hydroxy-Δ-9-tetrahydrocannabinol

KW - Cannabis active use

KW - Cut-Off

KW - GC–MS/MS

KW - Hair

KW - Metabolites of Δ–9–tetrahydrocannabinol

UR - http://www.scopus.com/inward/record.url?scp=85072613197&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85072613197&partnerID=8YFLogxK

U2 - 10.1016/j.forsciint.2019.109951

DO - 10.1016/j.forsciint.2019.109951

M3 - Article

AN - SCOPUS:85072613197

VL - 304

JO - Forensic Science International

JF - Forensic Science International

SN - 0379-0738

M1 - 109951

ER -