Optimizing screening cutoffs for drugs of abuse in hair using immunoassay for forensic applications

BACKGROUND

In forensic toxicology, positive immunoassay (IA) test results do not hold forensic validity and need to be confirmed with mass spectrometry (MS). On the other hand, a negative result is a strong indication that the drug and/or the drug metabolites are not present in the sample and that confirmatory analyses are not necessary. Consequently, a negative IA result must have forensic validity since it can be admitted in court during a trial.

OBJECTIVES

Screening cutoffs for the analysis of hair samples using immunoassays (IAs) were retrospectively optimized based on the Society of Hair Testing (SoHT) confirmation cutoffs and the utility of the test for forensic applications was discussed.

MATERIAL AND METHODS

Hair samples taken from 150 patients with a history of drug addiction were analyzed with ILab 650, Werfen (Milan, Italy) using DRI® reagents. Confirmatory analyses were subsequently performed using the ACQUITY UPLC® System, Waters Corporation (Milford, USA). Screening cutoffs were retrospectively optimized using receiver operating characteristic (ROC) analysis.

RESULTS

A total of 162 single positive results were obtained for confirmatory analysis (10 for amphetamines/methamphetamines, 11 for MDMA, 37 for cocaine, 40 for THC, 33 for methadone, and 31 for opiates). The optimized screening cutoffs were 0.27 IA ng/mg for amphetamines, 0.51 IA ng/mg for MDMA, 0.59 IA ng/mg for cocaine, 0.14 IA ng/mg for cannabinoids, 0.63 IA ng/mg for methadone, and 0.26 IA ng/mg for opiates. An area under the curve (AUC) greater than 0.95 was obtained with very high sensitivity and specificity for all drugs.

CONCLUSIONS

The presented screening method proved to be a useful technique on hair samples for the classes of drugs most commonly found in Italy and Europe and can be applied to forensic analysis.

Determination of ethyl glucuronide in hair and self-reported alcohol consumption in university students

Young individuals constitute an intriguing population, as their drinking habits are notably shaped by their perception of their peers' alcohol consumption. Nonetheless, excessive alcohol intake can have detrimental effects on academic performance, interpersonal relationships, and the risk and severity of accidents. This study reported the first data involving students enrolled from three universities on a voluntary basis for alcohol consumption evaluation. Alcohol consumption was assessed through questionnaires and EtG quantification in hair (hEtG) carried out by liquid chromatography-mass spectrometry (LC-MS/MS) analysis after a solid-phase extraction (SPE) purification step. The results of our study demonstrated that 77.1% of samples tested negative for hEtG or displayed hEtG ≤ 5 pg/mg. Particularly, the student population was not characterized by samples with hEtG indicative of chronic excessive consumption (hEtG ≥ 30 pg/mg). No significant association was identified between biological sex, among the degree course/the year attended, nor in relation to BMI or smoking/coffee consumption. Among the obtained results, it was worth noting that the comparison of self-reporting abstinence from tobacco and coffee accounted for 65.3% and 16.7%, respectively, while only 2.8% of the total declared abstinence from alcohol. The current study has uncovered a significant level of interest among students in this analysis and its interpretation. This suggests that implementing public health promotion activities within a university setting could be beneficial.

Per- and polyfluoroalkyl substances (PFAS) presence in food: Comparison among fresh, frozen and ready-to-eat vegetables

There is a worldwide discussion to provide safety limits in food for per- and polyfluoroalkyl substances (PFAS), a group of persistent contaminants associated to human disease. Processed food is more at risk of containing increased amounts of PFAS as a consequence of intentionally or non-intentionally contamination during manipulation and packaging. Among food products, also vegetables can be submitted to industrial manipulation; therefore, a different PFAS content correlated to the level of vegetables processing is conceivable. This study assessed the amount and type of PFAS present in fresh, frozen and ready-to-eat vegetables. Differences have been observed between the three groups of samples in the average PFAS content; the difference between ready-to eat and frozen vegetables resulted statistically significative. Organic vegetables displayed a lower total amount of PFAS respect to the traditional counterpart. The impact of industrial manipulation remains to be cleared, but pesticides use during cultivation could be considered a source of PFAS contamination.

Analysis and distribution of per- and polyfluoroalkyl substances in decidua and villi placenta explants

Placenta mediates the transfer of nutrients, oxygen and drugs from mother to fetus. It is constituted by two cellular layers separated by the intervillous space: the outer is in direct contact with maternal blood (decidua placenta), and the inner (villi) directly in contact with the fetus. Environmental contaminants, such as per- and polyfluoroalkyl substances (PFAS) also demonstrated the ability to cross the tissue multiple layers, posing at risk the health of the fetus. The aim of the present study was to analyse the PFAS amount in decidua and villi placenta explants and to study differences in their distribution among the two side of this organ. The determination of 23 PFAS was carried out by liquid chromatography coupled to high-resolution accurate mass spectrometry (LC-HRAM). Our research included women who delivered at term between 2021 and 2022. Our data indicated that all samples contained at least one PFAS, demonstrating the ubiquitarian presence of these compounds in our population. A high occurrence of PFOS, PFOA and PFHxS, followed by PFHxA, PFBS and PFUnA was found. The fluorotelomer 6:2 FTS was also present in more than 40% of samples and this represent the first data on placenta explants. Mean and median PFAS values for decidual explants were 0.5 ng/g and 0.4 ng/g (SD 0.3), while for villi explants mean and median values were 0.6 ng/g and 0.4 ng/g (SD 0.4). A different pattern of accumulation was observed between villi and decidual explants for PFOS, PFOA and PFUnA (villi > decidua) and PFHxA, PFHxS, PFBS and 6:2 FTS (decidua > villi). Even if the mechanism of this selectively accumuation is not yet understood, molecular degree of ionization and its lipophilicity could at least in part explain this difference. This study expands the limited data describing PFAS levels in the placenta and pose attention on PFAS exposure during pregnancy.

Valproic acid determination by liquid chromatography coupled to mass spectrometry (LC-MS/MS) in whole blood for forensic purposes

Valproic acid (VPA) is a well-known drug prescribed as anti-epileptic. It has a narrow therapeutic range and shows great individual differences in pharmacodynamics and pharmacokinetics. Consequently, the therapeutical drug monitoring (TDM) in patient's plasma is of crucial importance. Liquid chromatography coupled to mass spectrometry (LC-MS/MS) has gained importance in TDM applications for its features of sensitivity, selectivity and rapidity. However, in case of VPA, the LC-MS/MS selectivity could be hampered by the lack of a sufficient number of multiple reaction monitoring (MRM) transitions describing the molecule. In fact, the product ion scan of deprotonated molecules of VPA does not produce any ion and thus most LC-MS/MS methods are based on the detection of the unique MRM transition m/z 143➔143. In this way, the advantages of selectivity in LC-MS cannot be effectively exploited. In the present method, stable analyte adducts were exploited for the determination of VPA in blood. An Acquity HSS C18 column and mobile phases consisting of 5-mM ammonium formate and acetonitrile both added 0.1% formic acid were used. Source worked in negative acquisition mode and parameters were optimized to increase the adduct (m/z 189) and dimer (m/z 287) stability, and their fragmentation were used to increase the selectivity of MRM detection. The method has been validated according to the toxicological forensic guidelines and successfully applied to 10 real blood samples. Finally, the present method showed suitable for the rapid LC-MS/MS detection of VPA in whole blood, demonstrating the possibility to increase specificity by exploiting stable in-source adducts. This should be considered of utmost importance in the case of forensic applications.

Oral fluid analysis to monitor recent exposure to synthetic cannabinoids in a high-risk subpopulation

Among novel psychoactive substances, synthetic cannabinoid receptor agonists (SCRA) seem to have the widest diffusion in the population with no limitation to any particular demographic group. Information on drug consumption relies mostly on anonymized surveys and less on clinical or analytical data; notwithstanding, the huge efforts constantly made to enroll subjects to gather epidemiological data. In the present study, we collected 66 oral fluid samples from volunteers in a drug rehabilitation center in 2019 and early 2020. A liquid chromatography-mass spectrometry method previously developed and validated by our Unit was applied to detect SCRA (n = 10) in oral fluid. Results proved the presence of synthetic cannabinoids at a positivity rate of almost 20%, with detection frequency HU211(5/13) > UR144/JWH122 (3/13) > JWH019/JWH081/AM2201 (1/13). Concentrations were in the range < LOQ -0.36 ng/ml. Synthetic cannabinoids consumption had not been declared by any volunteer. This study enabled for the unprecedent detection of synthetic cannabinoids use in the territory of Parma (Italy) in a high-risk subpopulation. The identified SCRA proved the persistence into the market of the "first-generation" JWH family into the Italian territory and the marketing of relatively new ones (AM-2201). Public health consequences represented by NPS consumption are still scarce; therefore, further studies are needed to understand the real diffusion in the population.

The use of fly artifacts in a crime scene: Is there any application for forensic toxicology?

Fly artifacts (FA) are bloodstains resulting from insect activity at a crime scene, usually by feeding on human blood. Whether these artifactual stains might be useful for forensic toxicological investigations in cases of absence of conventional and unconventional matrices, for example, in cases concealment of the body or of extensive putrefaction, has not yet been investigated. The purpose of this study is to understand if FA trace evidence permits toxicological analysis when traditional matrices are not available. To this aim, FA experimentally produced by Calliphora vomitoria feeding on human blood of a cocaine and heroin user were collected from absorptive and non-absorptive material. FA material was analyzed by a new simple and fast LC-MS/MS method. Results were evaluated in terms of presence of the drug and relative amount of the detected molecules. From a qualitative point of view, the analysis of FA revealed all the substances originally detected in post-mortem blood in both cases. The ratios of cocaine/benzoylecgonine, codeine/morphine, and 6-monoacetylmorphine/morphine recovered in FA from cotton-textile materials and from non-absorptive surfaces were consistent with data resulted from original post-mortem blood. The preliminary study herein reported demonstrated that FA are extremely informative in case of cocaine and heroin users and merit further research in order to be applied in real caseworks.

Hair determination of per- and polyfluoroalkyl substances (PFAS) in the Italian population

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic chemicals present in the environment and defined as persistent organic pollutants (POPs). The interest in these forms of contaminants is related to the toxic consequences for health derived from exposures and bioaccumulation processes. The present research aims at assessing differences in the exposure of PFAS in the Italian population by hair analyses. To this aim, 20 compounds of the PFAS family were investigated in hair of 86 Italian subjects distributed across the regions of Veneto, Emilia-Romagna, Lombardy and Marche. The applied method was ad hoc developed in a previous research and included SPE extraction and LC-QTOF analysis. In the analyzed population, 66.4 % had quantifiable amounts of one or more PFAS molecules (up to 4 compounds); mean PFAS content, expressed as sum of PFAS, was 0.1457 ng/g, ranging from "not detected" to 0.85 ng/g (SD 0.1867). PFOA and PFOS were the chemicals most frequently detected, with mean concentrations of 0.1402 ng/g and 0.1155 ng/g, respectively. PFBA was detected in 9.3 % of subjects with a mean concentration of 0.3760 ng/g; PFNA in 3.5 % of subjects with mean concentration 0.12 ng/g; PFDA was found in one subject at the concentration of 0.541 ng/g. PFUnA and PFHxS were detected below the limit of quantification. The overall results displayed differences in the presence and prevalence of PFAS in hair of the Italian population on a geographical base. On the contrary, no significatively differences in the amount of PFAS were observed when considering gender or age classes. On this base, hair can be considered a good diagnostic tool to assess PFAS exposure on a regional-scaled base. Of course, more studies are required to infer PFAS internal dose from hair results due to its peculiar detection window and to interpretative issues derived from external contamination.

Automated sample preparation and analysis by gas chromatography tandem mass spectrometry (GC-MS/MS) for the determination of 3- and 2-monochloropropanediol (MCPD) esters and glycidol esters in edible oils

The potentially carcinogenic process contaminant 3- and 2-monochloropropanediol esters (2-MCPD and 3-MCPD esters) and glycidyl esters (GEs) are under study in refined oils and foodstuffs. Legislation set recommended total daily intake (TDI) for 3-MCPD of 0.8 µg/kg and as low as reasonably achievable (ALARA) for glycidol. Usually, the so far adopted method for the determination of these contaminants relay on numerous and time-consuming steps for sample preparation (AOCS methods) and on GC-MS detection. The obtained sensitivities and the number of processable samples are thus limited. In this optic, new reliable methods that allow for the fast and sensitive determination of these contaminants in edible oils may be considered an improvement of the overall strategy of tackling the problem. In this paper a new automated method for sample preparation and detection by GC-MS/MS is presented and validated. Data on sensitivity (LOD at 1.5, 2.2 and 3 ng/g for 3-MCPD, 2-MCPD, 3-MBPD (deriving from glycidol), respectively), linearity across low and high calibration ranges and precision showed to be fit-for-purposes. Finally, the methodology was applied to ten extra virgin oil samples and one sample of sunflower seeds oil.

Correction to: Is old stuff back? A fatal case of ethyl chloride sniffing

An amendment to this paper has been published and can be accessed via the original article.

New psychoactive substances: An actual problem or an overestimated phenomenon?

In last years, international and national Institutions have been completely focused on the new psychoactive substances (NPS) phenomenon. Many contrast policies have been planned in order to control their spread. Even scientific entities, such as our Forensic Toxicology Division, have spent time and resources for NPS identification in biological (from clinical and forensic caseworks) and non-biological (seized material) samples. Last reports show a low prevalence of NPS across the Europe and Italy, while the classical drugs are still the main cause of drug-related deaths. In particular, a worrisome datum is represented by the increasing number of deaths due to heroin. Seen these statistics, is the NPS phenomenon overestimated? Is the interest in classical drugs decreased? Were we diverted by NPS?

Psychotropic substance abuse and fitness to hold a driving license in Italy

Objective: Driving under the influence (DUI) of psychotropic substances is a serious and widespread problem in road safety. All countries try to reduce the impact with legislative controls over the criteria to regain a driver's license after suspension. In many European countries there are mandatory clinical and toxicological examinations required before a license is regranted. In Italy, individuals convicted of driving under the influence of drugs and/or alcohol must undergo a mandatory medico-legal and forensic toxicological examination prior to regranting of a license. This article reports on the prevalence, trends, and implications of psychotropic substances detected in more than 5,000 subjects submitted to driving license reissuance in the period 2011-2016. Methods: The study involved taking a clinical history, medical examination, and toxicological analysis of both urine and hair samples. Results: There was no change in the prevalence of psychoactive substances in the period 2011-2016. Cocaine was found most often (60%), followed by cannabinoids (15%) and opiates (9%). Methadone and amphetamine stimulants accounted for less than 5% each. Benzodiazepines were present in 15% of samples throughout the period. Conclusion: Cocaine and cannabinoids were the most used substances in the analyzed population, alone and in combination. Benzodiazepines were the most commonly detected prescription medication, raising questions about prescribed medication and driving risk that are not addressed by current legislation.

Internet pseudoscience: Testing opioid containing formulations with tampering potential

Drug tampering practices, with the aim to increase availability of drug delivery and/or enhance drug effects, are accessible on Internet and are practiced by some portion of recreational drug users. Not rarely, recreational misuse may result in toxic and even fatal results. The aim of the present study was to assess the tampering risk of medicaments containing different formulations of an opioid in combination with paracetamol or dexketoprofen, following the procedures reported in dedicated forums on the web. Tablets and suppositories containing codeine, tramadol and oxycodone were extracted following the reported "Cold water extraction"; dextromethorphan was extracted from cough syrup following the procedure reported as "Acid/base extraction" and fentanyl was extracted from transdermal patches according the procedure reported in Internet. The tampered products and opportunely prepared calibrators in water were analysed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The separation of the analytes was carried on Agilent ZORBAX Eclipse Plus C18 (RRHT 2.1 mm × 50 mm, 1.8 μm) by the gradient elution of 0.01% formic acid in water and 0.01% formic acid in methanol. Acquisition was by MRM mode considering at least two transitions for compound. Declared recoveries for these home-made extractions claimed to exceed 99% for the opioid and to complete remove paracetamol, often associated to liver toxicity and thus to obtain a "safer" preparation. In this study, the authors demonstrated that rarely the recoveries for the opioid reached 90% and that up to 60% of the paracetamol amount remained in solution. Thus, high risks for health remained both for the potential lethality of the opioid content, but also for the sub-lethal chronic use of these mixtures, which contained still uncontrolled, ignored, but often important amounts of paracetamol.

[Assessment of fitness to drive in correlation with narcotic and psychotropic drug use. Epidemiologic study in Verona]

Driving under the influence of drugs is a serious problem for road traffic safety. According to the Italian Road Traffic Code, the driving licence must not be issued to anyone who abuses, is addicted to, or suffers for dependence to illicit or psychotropic drugs. The diagnosis of such clinical conditions is performed by Provincial Medical Commissions of the Public Health Service also on the basis of drugs of abuse testing results on urine and/or hair samples. This study aimed at examining test results obtained by the Forensic Toxicology laboratory of the Department of Public Health & Community Medicine, University of Verona, upon request of the local Medical Commission, over the period 2003-2008 with the purposes of (i) defining trends in drug abuse in the examined population (ii) identifying specific risk factors for testing positive and for relapse, (iii) selecting the most effective and efficient analytical strategy to detect illicit drugs use. During the study period, cocaine was the most frequently detected illicit drug. The comparison of results from urine and hair testing confirmed the complementary features of these two biological substrates and the importance to have both data in order to increase the sensitivity in detecting illicit drug use. Moreover, this study showed that testing for driving fitness is an effective deterrent to illicit drug use, as only about one quarter of subjects testing positive at the first testing are still positive at the second testing.

Improved capillary electrophoresis determination of carbohydrate-deficient transferrin including on-line immunosubtraction

The instrumental analysis of carbohydrate-deficient transferrin (CDT), a recognized marker of chronic alcohol abuse, is most commonly carried out by high-performance liquid chromatography (HPLC) or capillary zone electrophoresis (CZE). Between these two techniques, CZE shows higher efficiency and productivity, but is often reported to be inferior to HPLC in terms of selectivity, because of a less specific ultraviolet detection wavelength than HPLC. On these grounds, the present work was aimed at the development of an improved CZE method for CDT determination, including an on-line immunosubtraction step specifically aimed at enhancing the analytical specificity of CZE determination. The analytical conditions were as follows: uncoated fused silica capillary, 30 microm x 60 cm (L = 50 cm to detector); running buffer, 100 mmol/L borate and 6 mmol/L DAB (1,4-diaminobutane), pH 8.3; voltage, 30 kV; temperature, 25 degrees C; detection, 200 nm. Under the described CZE conditions, a baseline separation between all the CDT related peaks was achieved with good analytical performances in terms of both precision and accuracy. In order to achieve unequivocal recognition of the CDT peaks, an in-capillary immunosubtraction step was included by loading a plug of anti-human transferrin antibody solution after the sample plug. This analytical approach was applied successfully to recognize CDT peaks in the presence of potential interferences.

Study of vitreous potassium correlation with time since death in the postmortem range from 2 to 110 hours using capillary ion analysis

The time-dependent postmortem increase of potassium concentration in the eye fluids has been studied since the 1960s. However, important discrepancies on the reproducibility of the phenomenon have hampered the use of this parameter in real cases. In recent years, a new analytical approach based on capillary ion analysis (CIA) has been reported. In the present work, the correlation between vitreous potassium and postmortem interval (PMI) has been re-evaluated by using CIA in a group of 164 cases with PMIs ranging from 2 to 110 hours. The correlation of the two parameters was described by the following regression equation: y = 0.1733x + 2.3008 (x = PMI; y = K(+) concentration); correlation coefficient = 0.962. The re-calculation of PMIs on the basis of this equation provided calculated PMIs with an average error of 5.54 hours (SD = 4.16). However, the percent PMI calculation error decreased with the increase of PMI, becoming acceptable for practical application above 24 hours since death.

Fully automated analysis of Carbohydrate-Deficient Transferrin (CDT) by using a multicapillary electrophoresis system

BACKGROUND

The techniques universally believed as most reliable for determination of Carbohydrate-Deficient Transferrin (CDT) are HPLC and capillary electrophoresis (CE). Recently a reagent kit for CDT analysis to be used in a multicapillary electropherograph has been introduced. The present work was aimed at a validation of this new commercial system by application of the analytical chemistry parameters and by comparison with validated CE and HPLC methods.

METHODS

One hundred forty serum samples were analyzed with multicapillary CE (Capillarys, Sebia, France) using kit reagents (CAPILLARYS CDT assay), with single capillary electropherograph (P/ACE MDQ, Beckman Coulter, USA) using an original method developed by our group and with HPLC, performed on a gradient HPLC (Shimadzu Europe, Germany), using column and reagents provided in kit (ClinRep, Recipe, Germany).

RESULTS

The separation efficiency of the multicapillary system was about 15,000 theoretical plates/column. The resolution of the transferrin isoforms ranged from 1.23 to 1.67. The variation coefficient was < 10% in both intra-run and between run tests. The correlation of results of multicapillary CE with those obtained with single CE and HPLC was statistically significant.

CONCLUSIONS

The multicapillary system shows high productivity with good analytical performances; however, a confirmation of positive results with an alternative method is required.

Current role of capillary electrophoretic/electrokinetic techniques in forensic toxicology

The current application of capillary electrophoresis in forensic toxicology has been critically reviewed with special focus on the areas where this technique has shown real advantages over chromatographic methods. For example, capillary electrophoresis has been most successfully applied to the chiral analysis of some drugs of forensic interest, including amphetamines and their congeners. Another typical application field of capillary electrophoresis is represented by protein analysis. Recently, special interest has been paid to carbohydrate deficient transferrin (CDT), the most important biological marker of chronic alcohol abuse. Other specific applications of capillary electrophoresis of potential forensic toxicological concern are also discussed. The review includes 62 references.

Direct analysis of bromide in human serum by capillary electrophoresis

The purpose of the present work was the development and validation of a simple, rapid and reliable method for direct bromide quantification in serum based on capillary electrophoresis (CE). The analysis was carried out with an automated capillary electropherograph. Analytical conditions were as follows. Capillary: uncoated fused silica, effective length 50 cm, internal diameter 50 microm; voltage: 20 kV in reverse polarity mode; temperature: 25 degrees C; running buffer: 90 mmol/L sodium tetraborate decahydrate and 10 mmol/L NaCl, pH 9.24; detection: direct UV absorption at 200 nm; sample treatment: dilution of serum 1:10 with the internal standard solution (2 mmol/L thiocyanate). Under the described conditions, bromide ions and internal standard were baseline separated in 7 min. No interferences from other serum components were observed. The analytical sensitivity was characterized by a LOD: 0.05 mmol/L and a LOQ of 0.1 mmol/L. Excellent linearity was verified in the range from 2.5 to 60 mmol/L [y = 0.0746x - 0.0372; R2 = 0.9995 (x = bromide concentration; y = bromide peak area/internal standard (I.S.) peak area)]. Quantitative imprecision in intra-day (n = 7) and day-to-day (n = 7) experiments was always within R.S.D. values <2%. Recovery was quantitative throughout the range of linearity of the method. Clinical cases of infants undergoing potassium bromide therapy for refractory epilepsy were analyzed with results in agreement with literature data. On the basis of these considerations, capillary electrophoresis can be proposed as the method of choice for bromide analysis in serum samples, especially for therapeutic drug monitoring purposes.