RESUMO
As cocaine is not only incorporated into hair via blood following ingestion but also by external contamination, hair samples are commonly tested for cocaine metabolites to prove ingestion. However, cocaine metabolites can also be present as degradation products in typical street cocaine samples. The present study investigates minor hydroxycocaine metabolites para- and meta-hydroxycocaine together with para- and meta-hydroxybenzoylecgonine in seized cocaine (n=200) and hair samples from routine casework (n=2,389). Analytical results of hair samples were interpreted using an established decision model for the differentiation between actual use and external contamination using metabolic ratios (metabolite to cocaine). They were further examined concerning background of request, hair color, body site of sample collection, sex, and metabolic ratios of the main metabolites (benzoylecgonine, norcocaine, and cocaethylene). All seized cocaine samples were positive for para- and meta-hydroxycocaine with a maximum percentage of 0.025 and 0.052 %, respectively; para- and meta-hydroxybenzoylecgonine were detected in 55 and 56 % of samples with a maximum percentage of 0.044 and 0.024 %, respectively. Analytical results of 424 hair samples (17.7 %) were interpreted as being predominantly from contamination; the majority of these samples were from traffic medicine cases (83.7 %). Metabolic ratios of minor hydroxycocaine metabolites were significantly higher in hair samples interpreted as originating from use than in samples interpreted as caused by contamination. Metabolic ratios for hydroxycocaines were significantly higher in forensic cases compared to abstinence controls and also in black hair compared to blond/gray hair. However, this was not the case for hydroxybenzoylecgonine metabolic ratios. No statistical difference was observed with regard to the donor's sex. Hydroxycocaine metabolic ratios increased significantly with increasing ratios of norcocaine and cocaethylene to cocaine, respectively. The study demonstrates that hydroxycocaine metabolites (including thresholds for their metabolic ratios) must be used for a reliable interpretation of positive cocaine results in hair samples.
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In forensic toxicology, high-performance liquid chromatography tandem mass spectrometry (LC-MS-MS) is increasingly used for the fast and sensitive measurement of a wide range of drugs. For our routine casework, a LC atmospheric pressure chemical ionization MS-MS method for the quantification of Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol (CBN) and cannabidiol (CBD) in hair was established and fully validated. Separation was achieved using a Kinetex® C18 column (100 mm × 2.1 mm, 100 Å, 1.7 µm, Phenomenex) at a flow rate of 0.5 mL/min. Measurements were performed on a QTRAP 5500 mass spectrometer (Sciex, Darmstadt, Germany). Unexpected signals were observed in authentic THC-positive hair samples. First, a signal with a slightly shifted retention time of THC whose origin could be assigned to the isomer Δ8-THC was detected. Second, additional peaks exhibiting the same fragments as CBN and Δ9-THC but eluting at different retention times were detected. Spiking experiments and enhanced product ion scans pointed to the origin of these additional signals as result of in-source decarboxylation of Δ9-tetrahydrocannabinolic acid A (Δ9-THCA-A) into Δ9-THC and further partial oxidation of Δ9-THC into CBN, respectively. Positive findings of Δ9-THCA-A in hair have been shown to derive from external contamination; therefore, the herein described artifacts may be used as indirect markers for external contamination.
Assuntos
Canabidiol , Canabinol , Artefatos , Canabidiol/análise , Canabinol/análise , Cromatografia Líquida , Dronabinol/análise , Cabelo/química , Espectrometria de Massas em Tandem/métodosRESUMO
In morphine intoxication cases, forensic toxicologists are frequently confronted with the question of if the individual was opioid-tolerant or opioid-naïve, which can be investigated by hair analysis. However, interpretation of results can be challenging. Here, we report on hair testing for morphine and its metabolite hydromorphone following morphine intoxication without tolerance and upon chronic use. Two consecutive hair samples were collected after a non-fatal intoxication. Analysis comprised short hair segments and their initial wash water solutions. In the intoxications, morphine and hydromorphone levels were 3.3 to 56 pg/mg and at maximum 9.8 pg/mg, respectively. Both levels and hydromorphone to morphine ratios were significantly lower compared to chronic morphine use. In the non-fatal intoxication, the highest hydromorphone to morphine ratio was obtained in the segment corresponding to the time of intoxication. Morphine ratios of wash to hair were significantly higher in the intoxications compared to chronic use, being indicative of sweat/sebum contamination. We recommend including the analysis of hydromorphone and the initial wash solution in cases of morphine intoxications. Our study demonstrates that hydromorphone to morphine ratios can help in distinguishing single from chronic morphine use and in estimating the period of exposure when a consecutive hair sample can be collected in survived intoxications.
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AIM: Due to the COVID-19 pandemic increasing the use of hand disinfectants, we investigated the effect of frequent use of ethanol-based hand disinfectants (EBHD) on the levels of the alcohol marker ethyl glucuronide (EtG) in hair. METHOD: Hair samples were collected from 10 health professionals (8 nondrinkers, 2 rarely drinking individuals) and EtG was examined in hair. RESULT: EtG (~2 pg/mg) was only detected in the hair sample of a nondrinker using EBHD 60-70 times per working day. CONCLUSION: Our data provide no evidence that frequent EBHD use results in hair EtG levels above the recommended Society of Hair Testing cutoff for repeated alcohol consumption (5 pg/mg).
Assuntos
Etanol/análise , Glucuronatos/análise , Cabelo/química , Higienizadores de Mão/análise , Pessoal de Saúde , Adulto , Feminino , Cabelo/efeitos dos fármacos , Higienizadores de Mão/administração & dosagem , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
Benzodiazepines (BDZ) and z-drugs belong to the most frequently prescribed medicines worldwide used for anxiety, epilepsy and sleeping disorders. Due to their pharmacology, they have a high potential for misuse. Hair analysis is being performed for the retrospective monitoring of drug exposure. However, there is a lack of reference values to obtain indication of BDZ/z-drug misuse. Further, there is no consensus on BDZ/z-drug cut-off concentrations above which a hair sample is reported as positive. The objective of the present study was to retrospectively evaluate BDZ/z-drug levels in hair for better interpretation of hair testing results. For this purpose, 4,630 authentic samples (head/body hair) from a heterogeneous cohort in Switzerland tested for the presence of 20 BDZ/BDZ metabolites and three z-drugs by liquid chromatography-tandem mass spectrometry were included. Drug concentrations in hair were statistically evaluated by box-plots in 1,726 positive samples. Further, metabolite-to-parent drug ratios were determined. Zolpidem, diazepam, nordazepam, oxazepam, lorazepam, midazolam, alprazolam, and bromazepam were among the most frequently detected drugs. Generally, drug concentration ranges varied strongly between the lower limit of quantification and 30,000â¯pg/mg hair. Sixteen BDZ/BDZ metabolites and zopiclone (z-drug) displayed a median below 50â¯pg/mg which is recommended as cut-off or minimum requirement for the limit of detection (LOD) by institutions. In case of ten drugs even the 75th percentile was below 50â¯pg/mg. Therefore, we strongly recommend to reconsider whether the use of an equal BDZ/z-drug cut-off is reasonable and whether minimum requirements for LODs should be lowered. The statistical evaluation of BDZ/Z-drug hair concentrations by box-plots can help in the development of analytical methods for hair samples and in the interpretation of BDZ/z-drug hair levels.
Assuntos
Compostos Azabicíclicos/química , Benzodiazepinas/química , Cabelo/química , Piperazinas/química , Cromatografia Líquida , Monitoramento de Medicamentos/métodos , Toxicologia Forense/métodos , Análise do Cabelo/métodos , Humanos , Limite de Detecção , Estudos Retrospectivos , Espectrometria de Massas em Tandem/métodosRESUMO
Recent studies indicate that not only the anthelminthic levamisole but also the racemate tetramisole (R-/S-phenyltetraimidazothiazole, PTHIT) was found as an adulterant for cocaine. We herein report on the investigation of the prevalence of PTHIT among cocaine-positive hair samples and the discrimination of the presence of its stereoisomers levamisole and dexamisole. Cocaine-positive hair samples were collected in a forensic context in 2015 and mainly 2017 (n = 724). Cocaine and PTHIT concentrations have been determined by achiral liquid chromatography-tandem mass spectrometry (LC-MS/MS). For distinction of levamisole/dexamisole chiral LC-MS/MS was performed. Cocaine hair concentrations ranged from 500 (cut-off) to approximately 800 000 pg/mg. The study demonstrates a strong prevalence of PTHIT in cocaine users' hair (87%, n = 627). PTHIT hair concentrations ranged from below LLOQ 3.5 to approximately 61 000 pg/mg (median: 260 pg/mg). Surprisingly, enantiomeric ratios of levamisole/dexamisole ranged from 0.17 to 1.34 (median: 0.63). Therefore, PTHIT-adulterated street cocaine samples (n = 24) seized between 2013 and 2016 were tested. Samples mainly contained racemic tetramisole (87.5%), only one sample contained levamisole only and two samples contained non-racemic PTHIT. Our experiments suggest that the presence of tetramisole in biological samples may have hitherto been underestimated. Most probably higher dexamisole than levamisole concentrations in hair specimens arise from stereoselective metabolism and/or elimination. This is particularly important in light of the different pharmacological activities of the two enantiomers and potentially different adverse effects. Toxicological interpretations in intoxication cases with adulterated cocaine should not only consider levamisole but also tetramisole and terminology in scientific contributions should be used accordingly.
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Cocaína/análise , Contaminação de Medicamentos , Cabelo/química , Levamisol/análise , Tetramizol/análise , Animais , Cromatografia Líquida , Feminino , Humanos , Masculino , Ovinos , Espectrometria de Massas em TandemRESUMO
Despite irrefutable evidence of its negative impact on animal behaviour and physiology, lethal and sublethal lead poisoning of wildlife is still persistent and widespread. For scavenging birds, ingestion of ammunition, or fragments thereof, is the major exposure route. In this study, we examined the occurrence of lead in four avian scavengers of Switzerland and how it differs between species, regions, and age of the bird. We measured lead concentration in liver and bone of the two main alpine avian scavengers (golden eagle Aquila chrysaetos and bearded vulture Gypaetus barbatus) over the entire area of the Swiss Alps and two of the main avian scavengers occurring in the lowlands of Switzerland (red kite Milvus milvus and common raven Corvus corax). Of those four species, only the bearded vulture is an obligate scavenger. We found that lead burdens in the two alpine avian scavengers were higher than those found for the same species elsewhere in Europe or North America and reached levels compatible with acute poisoning, whereas lead burdens of the two lowland avian scavengers seemed to be lower. Several golden eagles, but only one red kite with abnormally high bone lead concentrations were found. In all four species, a substantial proportion of birds had elevated levels which presumably represent recent (liver lead levels) or past (bone lead levels) uptake of sublethal doses of lead.
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Aves , Exposição Ambiental/análise , Poluentes Ambientais/análise , Intoxicação por Chumbo/veterinária , Chumbo/análise , Fatores Etários , Animais , Comportamento Animal , Osso e Ossos/química , Corvos , Águias , Ecotoxicologia/métodos , Poluentes Ambientais/farmacocinética , Falconiformes , Chumbo/farmacocinética , Fígado/química , Especificidade da Espécie , Suíça , Distribuição TecidualRESUMO
Hair analysis has been established as a prevalent tool for retrospective drug monitoring. In this study, different extraction solvents for the determination of drugs of abuse and pharmaceuticals in hair were evaluated for their efficiency. A pool of authentic hair from drug users was used for extraction experiments. Hair was pulverized and extracted in triplicate with seven different solvents in a one- or two-step extraction. Three one- (methanol, acetonitrile, and acetonitrile/water) and four two-step extractions (methanol two-fold, methanol and methanol/acetonitrile/formate buffer, methanol and methanol/formate buffer, and methanol and methanol/hydrochloric acid) were tested under accurately equal experimental conditions. The extracts were directly analyzed by liquid chromatography-tandem mass spectrometry for opiates/opioids, stimulants, ketamine, selected benzodiazepines, antidepressants, antipsychotics, and antihistamines using deuterated internal standards. For most analytes, a two-step extraction with methanol did not significantly improve the yield compared to a one-step extraction with methanol. Extraction with acetonitrile alone was least efficient for most analytes. Extraction yields of acetonitrile/water, methanol and methanol/acetonitrile/formate buffer, and methanol and methanol/formate buffer were significantly higher compared to methanol. Highest efficiencies were obtained by a two-step extraction with methanol and methanol/hydrochloric acid, particularly for morphine, 6-monoacetylmorphine, codeine, 6-acetylcodeine, MDMA, zopiclone, zolpidem, amitriptyline, nortriptyline, citalopram, and doxylamine. For some analytes (e.g., tramadol, fluoxetine, sertraline), all extraction solvents, except for acetonitrile, were comparably efficient. There was no significant correlation between extraction efficiency with an acidic solvent and the pka or log P of the analyte. However, there was a significant trend for the extraction efficiency with acetonitrile to the log P of the analyte. The study demonstrates that the choice of extraction solvent has a strong impact on hair analysis outcomes. Therefore, validation protocols should include the evaluation of extraction efficiency of drugs by using authentic rather than spiked hair. Different extraction procedures may contribute to the scatter of quantitative results in inter-laboratory comparisons. Harmonization of extraction protocols is recommended, when interpretation is based on same cut-off levels.
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Cabelo/química , Entorpecentes/análise , Preparações Farmacêuticas/análise , Solventes , Detecção do Abuso de Substâncias , Acetonitrilas , Cromatografia Líquida , Formiatos , Humanos , Metanol , Transtornos Relacionados ao Uso de Substâncias/diagnóstico , Espectrometria de Massas em TandemRESUMO
To estimate drug consumption more reliably, wastewater-based epidemiology would benefit from a better understanding of drug residue stability during in-sewer transport. We conducted batch experiments with real, fresh wastewater and sewer biofilms. Experimental conditions mimic small to medium-sized gravity sewers with a relevant ratio of biofilm surface area to wastewater volume (33 m2 m-3). The influences of biological, chemical, and physical processes on the transformation of 30 illicit drug and pharmaceutical residues were quantified. Rates varied among locations and over time. Three substances were not stable-that is, >20% transformation, mainly due to biological processes-at least for one type of tested biofilm for a residence time ≤2 h: amphetamine, 6-acetylcodeine, and 6-monoacetylmorphine. Cocaine, ecgonine methyl ester, norcocaine, cocaethylene, and mephedrone were mainly transformed by chemical hydrolysis and, hence, also unstable in sewers. In contrast, ketamine, norketamine, O-desmethyltramadol, diclofenac, carbamazepine, and methoxetamine were not substantially affected by in-sewer processes under all tested conditions and residence times up to 12 h. Our transformation rates include careful quantification of uncertainty and can be used to identify situations in which specific compounds are not stable. This will improve accuracy and uncertainty estimates of drug consumption when applied to the back-calculation.
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Biofilmes , Águas Residuárias/química , Resíduos de Drogas , Drogas Ilícitas , Esgotos/químicaRESUMO
BACKGROUND: Compared to blood or urine, drugs can be detected for much longer periods in the long hair of horses. The aim of this study was to establish and validate a highly sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the detection and quantification of frequently prescribed opioids, sedatives and non-steroidal anti-inflammatory agents in the mane and tail hair of horses. Based on an average growth rate of about 2 cm per month, times of administration reported by horse owners or veterinary physicians were related to drug localizations in hair. Hair samples were collected from ten horses that received drug treatments and analyzed in segments of 2, 4 or 6 cm in length. Hair segments were decontaminated, cut into fragments and methanol-extracted under sonication. The extracts were analyzed by LC-MS/MS for 13 commonly used drugs using the validated procedure. Deuterated analogs were included as internal standards. RESULTS: Analytes were detected in hair samples with a length of up to 70 cm. Fourteen out of 16 hair samples were positive for at least one of the tested drugs. Segmentation allowed for time-resolved monitoring of periods of 1 to 3 months of drug administration. Concentrations in dark hair reached a maximum of 4.0 pg/mg for butorphanol, 6.0 pg/mg for tramadol, 1.4 pg/mg for morphine, 1.8 pg/mg for detomidine, 1.2 pg/mg for acepromazine, 39 pg/mg for flunixin, 5.0 pg/mg for firocoxib, and 3'600 pg/mg for phenylbutazone. Only trace amounts of meloxicam were detected. Drug detection correlated well with the reported period of medical treatment. No analytes were detected in the light-colored mane and tail hair samples from one horse despite preceding administrations of acepromazine and phenylbutazone. CONCLUSION: This study describes a sensitive and selective technique suitable for the validated detection and quantification of frequently prescribed veterinary drugs in horse hair. The segmental method can be applied for time-resolved long-term retrospective drug monitoring, for example in prepurchase examinations of horses as drug detection in hair can prove preceding medical treatments.
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Analgésicos Opioides/análise , Anti-Inflamatórios não Esteroides/análise , Cromatografia Líquida/veterinária , Cabelo/química , Cavalos , Hipnóticos e Sedativos/análise , Espectrometria de Massas em Tandem/veterinária , Analgésicos Opioides/farmacocinética , Animais , Anti-Inflamatórios não Esteroides/farmacocinética , Hipnóticos e Sedativos/farmacocinética , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Identification of external contamination is a challenge in hair analysis. This study investigates metabolite ratios of hydromorphone to morphine and hydrocodone to codeine as indicators to distinguish contamination from heroin use provided that hydromorphone/hydrocodone intake is excluded. RESULTS: Hair samples after external contamination with street heroin proved to be negative for hydromorphone/hydrocodone. Hair samples from individuals with suspected street heroin use/contamination or opiate medication were analyzed for 6-monoacetylmorphine, morphine, acetylcodeine, codeine, hydromorphone and hydrocodone, and metabolite ratios of hydromorphone to morphine and hydrocodone to codeine were assessed. Hair samples from individuals with medicinal heroin/morphine/codeine use displayed significantly higher metabolite ratios than those with suspected street heroin use/contamination. CONCLUSION: Hydromorphone/hydrocodone are solely formed during body passage. Thus, metabolite ratios can be used to distinguish morphine/heroin use from external contamination.
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Analgésicos Opioides/análise , Cabelo/química , Heroína/análise , Hidrocodona/análise , Hidromorfona/análise , Alcaloides Opiáceos/análise , Detecção do Abuso de Substâncias/métodos , Cromatografia Líquida/métodos , Feminino , Dependência de Heroína/diagnóstico , Humanos , Masculino , Morfina/análise , Derivados da Morfina/análise , Espectrometria de Massas em Tandem/métodosRESUMO
Incorporation rates of the enantiomers of 3,4-methylenedioxymethamphetamine (MDMA) and its metabolite 3,4-methylenedioxyamphetamine (MDA) into hair and nails were investigated after controlled administration. Fifteen subjects without MDMA use received two doses of 125 mg of MDMA. Hair, nail scrapings, and nail clippings were collected 9-77 days after the last administration (median 20 days). Hair samples were analyzed in segments of 1- to 2-cm length. After chiral derivatization with N-(2,4-dinitro-5-fluorophenyl)-L-valinamide, MDMA and MDA diastereomers were analyzed by liquid chromatography-tandem mass spectrometry. Highest concentrations in hair segments corresponded to the time of MDMA intake. They ranged from 101 to 3200 pg/mg and 71 to 860 pg/mg for R- and S-MDMA, and from 3.2 to 116 pg/mg and 4.4 to 108 pg/mg for R- and S-MDA, respectively. MDMA and MDA concentrations in nail scrapings and clippings were significantly lower than in hair samples. There was no significant difference between enantiomeric ratios of R/S-MDMA and R/S-MDA in hair and nail samples (medians 2.2-2.4 for MDMA and 0.85-0.95 for MDA). Metabolite ratios of MDA to MDMA were in the same range in hair and nail samples (medians 0.044-0.055). Our study demonstrates that administration of two representative doses of MDMA was detected in the hair segments corresponding to the time of intake based on average hair growth rates. MDMA was detected in all nail samples regardless of time passed after intake. Comparable R/S ratios in hair and nail samples may indicate that incorporation mechanisms into both matrices are comparable.
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Cabelo/química , Drogas Ilícitas/química , N-Metil-3,4-Metilenodioxianfetamina/química , Unhas/química , Detecção do Abuso de Substâncias/métodos , 3,4-Metilenodioxianfetamina/química , 3,4-Metilenodioxianfetamina/metabolismo , Cabelo/metabolismo , Humanos , Drogas Ilícitas/metabolismo , Pessoa de Meia-Idade , N-Metil-3,4-Metilenodioxianfetamina/administração & dosagem , N-Metil-3,4-Metilenodioxianfetamina/metabolismo , Unhas/metabolismo , EstereoisomerismoRESUMO
BACKGROUND: Toenails were assessed as an alternative matrix to hair for retrospective monitoring of cocaine consumption of recreational and dependent users. Results/methodology: Toenail clippings, scrapings and hair samples from recreational and dependent cocaine users were analyzed for cocaine and metabolites. Dependent users displayed significantly higher concentrations in hair and toenail samples compared to recreational users. Cocaine abstinence could be monitored in hair and toenail samples. One postmortem fingernail was analyzed in layers to investigate the cocaine and metabolite concentration profile. Highest concentrations were observed in the dorsal layer, being indicative of contamination. CONCLUSION: Having led to comparable results, toenails may be an alternative for retrospective monitoring of cocaine consumption/abstinence. Hair should remain the first choice for assessment of temporal evidence of drug intake.
Assuntos
Testes de Química Clínica/métodos , Transtornos Relacionados ao Uso de Cocaína/diagnóstico , Cocaína/análise , Cabelo/química , Unhas/química , Recreação , Métodos Analíticos de Preparação de Amostras , Cromatografia Líquida , Cocaína/metabolismo , Humanos , Estudos Retrospectivos , Espectrometria de Massas em Tandem , Fatores de TempoRESUMO
Nails are attracting increasing interest in forensic toxicology as an alternative to hair. The goal of this study was to systematically investigate the incorporation of drugs in fingernails after single drug dose, exemplified for zolpidem. Fingernail samples from ring fingers were collected one week before, and then 24 h and weekly after intake for a period of three to five months. Hair samples were taken six weeks after intake. Nail specimens were pulverized and extracted with methanol (internal standard: zolpidem-D6 ) under sonication. Extracts were analyzed by a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method, which was developed and validated for this study. The lower limit of quantification (LLOQ) for a 5-mg sample was 0.1 pg/mg nail. Zolpidem was detected continuously in fingernail clippings. The mean window of detection of zolpidem in fingernail clippings was 3.5 months. Unwashed nail specimens taken 24 h after intake showed the highest zolpidem concentrations indicating external contamination by sweat. External contamination experiments revealed that zolpidem could be incorporated in fingernails by sweat to such an extent that it remained irremovable by daily hygiene. Averagely 3 months after intake a concentration peak was reached, suggesting outgrowth of the nail part which had been formed while the drug circulated in blood. Hair concentrations were higher than the maximum nail concentrations. Pigmented hair contained more zolpidem than non-pigmented hair from the same strand. From all these results it can be concluded, that fingernail clippings may represent a useful alternative and/or complementary matrix in cases of, for example, drug-facilitated sexual assault or monitoring of constant consumption behavior.
Assuntos
Cromatografia Líquida/métodos , Hipnóticos e Sedativos/farmacocinética , Unhas/química , Piridinas/farmacocinética , Adulto , Toxicologia Forense/métodos , Cabelo/química , Humanos , Limite de Detecção , Pessoa de Meia-Idade , Espectrometria de Massas por Ionização por Electrospray/métodos , Detecção do Abuso de Substâncias/métodos , Espectrometria de Massas em Tandem/métodos , Fatores de Tempo , ZolpidemRESUMO
Tramadol was found in a man's hair sample during an abstinence test necessary to regain his driving license. The suspect denied having taken tramadol claiming external contamination as the reason for the positive result, as he was working in a tramadol production company. Nevertheless, low concentrations of both major metabolites, N-desmethyltramadol (NDMT) and O-desmethyltramadol (ODMT), were found in hair (180 and 6 pg/mg hair, respectively). To assess this case, tramadol concentrations and metabolite to parent drug concentration ratios were determined in hair samples of 75 patients taking tramadol and of eight employees working in the production and laboratory site of the same company. Additionally, wash water used for decontaminating hair was analyzed for both groups, patients and employees. Analysis of hair sample extracts was performed by LC-MS/MS using multiple reaction monitoring (MRM), information dependent acquisition (IDA) and enhanced product ion scan (EPI). High variations of metabolite to parent drug concentration ratios in hair samples of patients were observed. Differences in NDMT and ODMT to tramadol concentration ratios were found when comparing the cohort of patients to employees. The suspect could be included in the cohort of employees considering the ODMT to tramadol concentration ratio in hair and tramadol concentration ratio in wash water versus hair. Metabolite to parent drug concentration ratios of hair samples may represent a helpful tool for the differentiation of tramadol intake versus external contamination. Ratios of tramadol concentrations in wash water versus the subjects' hair may provide additional information for case assessments.