Workplace drug testing on urine samples: Evidence for improving efficacy of a first-level screening programme

Valeria Crespi, Ramòna Consuelo Maio, G. Veronesi, F. Gianfagna, S. Taborelli, M. M. Ferrario

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Background: Previous reports revealed poor performance in identifying drugs of abuse users through first-level workplace drug testing (WDT), based on urine samples. In a cross-sectional study, we evaluated: (i) the effect of creatinine normalization of drug values from diluted urine samples (creatinine levels ≤20 mg/dL) on the prevalence of drug users; (ii) the independent procedure-related predictors of positivity and dilution. Methods: Workers' urine samples were collected at the workplace or at our certified laboratory between 2008 and 2012. All samples were analysed for drugs of abuse by immuno-enzymatic method in our laboratory, according to the Italian WDT law. Detectable drugs of abuse concentrations lower than the positive cutoff values were normalized based on mean levels of urinary creatinine. Detectable concentrations of drugs were confirmed by GC/MS. Multivariate logistic regression was used to detect independent procedure-related predictors of positive and diluted urine samples. Results: Of the 3080 urine samples screened, 51 (1.7%) were found positive for some drugs of abuse (26 cannabinoids and 16 cocaine) and 116 (3.8%) were diluted. Seventeen out of 23 diluted urine samples with detectable concentrations of cannabinoids or cocaine were found positive after urine creatinine normalization and GC/MS confirmed both negative and positive results. This increased the percentage of positivity for cannabinoids and cocaine from 1.35% to 2.09% (+55%, p=0.0005), which is closer to the expected prevalence of drug users based on Italian self-reported surveys. Collection of samples in the laboratory was an independent predictor of positivity (OR=2.33, 95%CI 1.27-4.28) and diluted urine sample (OR=1.65, 95%CI 1.04-2.61). Conclusions: Efficacy of first-level WDT could be improved by well-controlled pre-Analytical procedures and urine creatinine normalization of detected concentrations of drugs of abuse.

Original languageEnglish
Pages (from-to)374-385
Number of pages12
JournalMedicina del Lavoro
Volume106
Issue number5
Publication statusPublished - 2015

Fingerprint

Workplace
Urine
Street Drugs
Pharmaceutical Preparations
Creatinine
Cannabinoids
Drug Users
Cocaine
Drug Legislation
Cross-Sectional Studies
Logistic Models

Keywords

  • Diluted urine sample
  • Drugs of abuse
  • Prevention policies
  • Public safety
  • Urine creatinine normalization
  • Workplace drug testing

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

Cite this

Crespi, V., Maio, R. C., Veronesi, G., Gianfagna, F., Taborelli, S., & Ferrario, M. M. (2015). Workplace drug testing on urine samples: Evidence for improving efficacy of a first-level screening programme. Medicina del Lavoro, 106(5), 374-385.

Workplace drug testing on urine samples : Evidence for improving efficacy of a first-level screening programme. / Crespi, Valeria; Maio, Ramòna Consuelo; Veronesi, G.; Gianfagna, F.; Taborelli, S.; Ferrario, M. M.

In: Medicina del Lavoro, Vol. 106, No. 5, 2015, p. 374-385.

Research output: Contribution to journalArticle

Crespi, V, Maio, RC, Veronesi, G, Gianfagna, F, Taborelli, S & Ferrario, MM 2015, 'Workplace drug testing on urine samples: Evidence for improving efficacy of a first-level screening programme', Medicina del Lavoro, vol. 106, no. 5, pp. 374-385.
Crespi, Valeria ; Maio, Ramòna Consuelo ; Veronesi, G. ; Gianfagna, F. ; Taborelli, S. ; Ferrario, M. M. / Workplace drug testing on urine samples : Evidence for improving efficacy of a first-level screening programme. In: Medicina del Lavoro. 2015 ; Vol. 106, No. 5. pp. 374-385.
@article{cf40591ba140442e9beb25bb1819660e,
title = "Workplace drug testing on urine samples: Evidence for improving efficacy of a first-level screening programme",
abstract = "Background: Previous reports revealed poor performance in identifying drugs of abuse users through first-level workplace drug testing (WDT), based on urine samples. In a cross-sectional study, we evaluated: (i) the effect of creatinine normalization of drug values from diluted urine samples (creatinine levels ≤20 mg/dL) on the prevalence of drug users; (ii) the independent procedure-related predictors of positivity and dilution. Methods: Workers' urine samples were collected at the workplace or at our certified laboratory between 2008 and 2012. All samples were analysed for drugs of abuse by immuno-enzymatic method in our laboratory, according to the Italian WDT law. Detectable drugs of abuse concentrations lower than the positive cutoff values were normalized based on mean levels of urinary creatinine. Detectable concentrations of drugs were confirmed by GC/MS. Multivariate logistic regression was used to detect independent procedure-related predictors of positive and diluted urine samples. Results: Of the 3080 urine samples screened, 51 (1.7{\%}) were found positive for some drugs of abuse (26 cannabinoids and 16 cocaine) and 116 (3.8{\%}) were diluted. Seventeen out of 23 diluted urine samples with detectable concentrations of cannabinoids or cocaine were found positive after urine creatinine normalization and GC/MS confirmed both negative and positive results. This increased the percentage of positivity for cannabinoids and cocaine from 1.35{\%} to 2.09{\%} (+55{\%}, p=0.0005), which is closer to the expected prevalence of drug users based on Italian self-reported surveys. Collection of samples in the laboratory was an independent predictor of positivity (OR=2.33, 95{\%}CI 1.27-4.28) and diluted urine sample (OR=1.65, 95{\%}CI 1.04-2.61). Conclusions: Efficacy of first-level WDT could be improved by well-controlled pre-Analytical procedures and urine creatinine normalization of detected concentrations of drugs of abuse.",
keywords = "Diluted urine sample, Drugs of abuse, Prevention policies, Public safety, Urine creatinine normalization, Workplace drug testing",
author = "Valeria Crespi and Maio, {Ram{\`o}na Consuelo} and G. Veronesi and F. Gianfagna and S. Taborelli and Ferrario, {M. M.}",
year = "2015",
language = "English",
volume = "106",
pages = "374--385",
journal = "Medicina del Lavoro",
issn = "0025-7818",
publisher = "Mattioli 1885 S.p.A.",
number = "5",

}

TY - JOUR

T1 - Workplace drug testing on urine samples

T2 - Evidence for improving efficacy of a first-level screening programme

AU - Crespi, Valeria

AU - Maio, Ramòna Consuelo

AU - Veronesi, G.

AU - Gianfagna, F.

AU - Taborelli, S.

AU - Ferrario, M. M.

PY - 2015

Y1 - 2015

N2 - Background: Previous reports revealed poor performance in identifying drugs of abuse users through first-level workplace drug testing (WDT), based on urine samples. In a cross-sectional study, we evaluated: (i) the effect of creatinine normalization of drug values from diluted urine samples (creatinine levels ≤20 mg/dL) on the prevalence of drug users; (ii) the independent procedure-related predictors of positivity and dilution. Methods: Workers' urine samples were collected at the workplace or at our certified laboratory between 2008 and 2012. All samples were analysed for drugs of abuse by immuno-enzymatic method in our laboratory, according to the Italian WDT law. Detectable drugs of abuse concentrations lower than the positive cutoff values were normalized based on mean levels of urinary creatinine. Detectable concentrations of drugs were confirmed by GC/MS. Multivariate logistic regression was used to detect independent procedure-related predictors of positive and diluted urine samples. Results: Of the 3080 urine samples screened, 51 (1.7%) were found positive for some drugs of abuse (26 cannabinoids and 16 cocaine) and 116 (3.8%) were diluted. Seventeen out of 23 diluted urine samples with detectable concentrations of cannabinoids or cocaine were found positive after urine creatinine normalization and GC/MS confirmed both negative and positive results. This increased the percentage of positivity for cannabinoids and cocaine from 1.35% to 2.09% (+55%, p=0.0005), which is closer to the expected prevalence of drug users based on Italian self-reported surveys. Collection of samples in the laboratory was an independent predictor of positivity (OR=2.33, 95%CI 1.27-4.28) and diluted urine sample (OR=1.65, 95%CI 1.04-2.61). Conclusions: Efficacy of first-level WDT could be improved by well-controlled pre-Analytical procedures and urine creatinine normalization of detected concentrations of drugs of abuse.

AB - Background: Previous reports revealed poor performance in identifying drugs of abuse users through first-level workplace drug testing (WDT), based on urine samples. In a cross-sectional study, we evaluated: (i) the effect of creatinine normalization of drug values from diluted urine samples (creatinine levels ≤20 mg/dL) on the prevalence of drug users; (ii) the independent procedure-related predictors of positivity and dilution. Methods: Workers' urine samples were collected at the workplace or at our certified laboratory between 2008 and 2012. All samples were analysed for drugs of abuse by immuno-enzymatic method in our laboratory, according to the Italian WDT law. Detectable drugs of abuse concentrations lower than the positive cutoff values were normalized based on mean levels of urinary creatinine. Detectable concentrations of drugs were confirmed by GC/MS. Multivariate logistic regression was used to detect independent procedure-related predictors of positive and diluted urine samples. Results: Of the 3080 urine samples screened, 51 (1.7%) were found positive for some drugs of abuse (26 cannabinoids and 16 cocaine) and 116 (3.8%) were diluted. Seventeen out of 23 diluted urine samples with detectable concentrations of cannabinoids or cocaine were found positive after urine creatinine normalization and GC/MS confirmed both negative and positive results. This increased the percentage of positivity for cannabinoids and cocaine from 1.35% to 2.09% (+55%, p=0.0005), which is closer to the expected prevalence of drug users based on Italian self-reported surveys. Collection of samples in the laboratory was an independent predictor of positivity (OR=2.33, 95%CI 1.27-4.28) and diluted urine sample (OR=1.65, 95%CI 1.04-2.61). Conclusions: Efficacy of first-level WDT could be improved by well-controlled pre-Analytical procedures and urine creatinine normalization of detected concentrations of drugs of abuse.

KW - Diluted urine sample

KW - Drugs of abuse

KW - Prevention policies

KW - Public safety

KW - Urine creatinine normalization

KW - Workplace drug testing

UR - http://www.scopus.com/inward/record.url?scp=84949509468&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84949509468&partnerID=8YFLogxK

M3 - Article

C2 - 26384263

AN - SCOPUS:84949509468

VL - 106

SP - 374

EP - 385

JO - Medicina del Lavoro

JF - Medicina del Lavoro

SN - 0025-7818

IS - 5

ER -