Drug Testing and Analysis最新文献

Autologous blood transfusions (ABTs) are prohibited by the World Anti-Doping Agency (WADA), yet detecting autologous blood micro-transfusions (ABMTs) remains a challenge. Due to smaller transfused volumes, ABMTs cause attenuated biomarker changes, limiting detection sensitivity within the Athlete Biological Passport (ABP). This study assessed whether mRNA expression of 5-aminolevulinic acid synthase (ALAS2) and carbonic anhydrase 1 (CA1), measured from dried blood spots (DBS), could serve as sensitive biomarkers of ABMT. In a randomized, placebo-controlled design, 47 trained individuals (24 ♀; mean VO₂peak 56 ± 7 mL·min⁻¹·kg⁻¹) were allocated to an ABMT group (n = 23; ♀ = 12) or placebo group (n = 24; ♀ = 12). The ABMT group donated 450 mL of blood and received a 130 mL packed red blood cell reinfusion 4 weeks later. Blood sampling occurred regularly before and after both donation and reinfusion. ALAS2 and CA1 mRNA expression from DBS, and reticulocyte percentage (RET%) from venous blood, were analyzed. Following blood donation, ALAS2, CA1, and RET% increased by 270%, 200%, and 150%, respectively. However, no consistent group-level changes were observed after ABMT. Individualized analysis identified more outliers for ALAS2 than for CA1, and blinded interpretation of individual mRNA profiles achieved > 95% sensitivity and specificity for detecting ABMT. These findings suggest that ALAS2 mRNA expression, assessed via minimally invasive DBS sampling, is a promising biomarker for identifying ABMT. This approach may enhance current anti-doping strategies by improving sensitivity to small-volume autologous transfusions that evade detection through traditional ABP biomarkers.

Methamphetamine is relatively uncommon on the European drug market, but Swedish drug test laboratories repeatedly detect low methamphetamine concentrations in urine samples containing high amphetamine levels, warranting clinical evaluation for suspected polydrug use. Of 12,062 routine samples screened positive for amphetamines, 86% were confirmed positive (≥ 200 μg/L) for amphetamine, 2.1% for methamphetamine, and 4.0% for 3,4-methylenedioxymethamphetamine (ecstasy) by liquid chromatography–tandem mass spectrometry. Of the 259 methamphetamine-positive samples, 98% contained amphetamine concentrations above the reporting limit, consistent with the metabolic conversion of methamphetamine to amphetamine in the body. However, in most (69%) of these samples, the methamphetamine concentration was only < 2% of the amphetamine level, suggesting methamphetamine was not the primary drug taken. Chiral analysis of selected samples showed that after use of illicit street amphetamine with a racemic content of the l- and d-enantiomers, a similar l/d proportion was observed for methamphetamine. Similarly, in samples from patients receiving d-amphetamine-based ADHD medication, low d-methamphetamine levels were detected, even though the pharmaceutical products contained no methamphetamine. This observation, together with the parallel l/d-enantiomer distributions, supports amphetamine N-methylation as a trace, albeit quantitatively insignificant, metabolic pathway in humans. From both a clinical and forensic perspective, a low urinary methamphetamine concentration of less than a few percent of the amphetamine level therefore does not warrant further clinical evaluation for suspected polydrug use. The present findings further demonstrate that chiral analysis of both amphetamine and methamphetamine is an effective approach for distinguishing between illicit and therapeutic sources in positive screening drug tests for the amphetamines.

Forensic hair analysis poses a valuable tool for assessing opioid exposure in children and neonates. However, reliable literature data on opioid concentrations in the hair of this population are mostly scarce, making the interpretation of such hair analysis results rather challenging. This noninterventional study aims to address this issue by investigating 118 hair samples of pediatric patients (median age: 50 days) from the University Children's Hospital Zurich. These patients were treated with medically approved novel synthetic opioids (fentanyl, remifentanil, sufentanil, or alfentanil) and traditional opioids (morphine, methadone, and hydromorphone) during their clinical treatment. Quantification of the opioids and selected metabolites was achieved by a previously validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) based method, which showed good sensitivity with lower limits of quantification (LLOQs) ranging from 0.1 to 1 pg/mg hair. Most analytes were successfully detected in patients' hair, with the majority being identified for the first time in this matrix. Significant correlations were found between the opioid concentrations in hair and the administered medication doses, indicating that hair analysis may reflect the extent of opioid exposure in this population. Furthermore, metabolite ratios similar to the ones commonly found in adult hair were identified, which are forensically important to differentiate between active intake of a drug and contamination. The metabolite ratio of β-hydroxyfentanyl to fentanyl was particularly well suited for children and neonatal patients. In conclusion, concentration ranges, metabolite ratios, and dose correlations of the studied opioids in pediatric hair were established, providing insights into opioid incorporation pathways.

Monitoring long-term alcohol consumption is critical in forensic and public health contexts. Hair analysis of ethyl glucuronide (EtG), a direct metabolite of ethanol, has become a standard method for detecting chronic alcohol use. While the reliability of EtG hair testing is well established for short- and medium-term analyses, its stability in hair stored over extended periods has not been comprehensively evaluated. This limitation is especially relevant in retrospective investigations, postmortem evaluations, and long-term epidemiological studies, where archived samples may be analyzed years after collection. In this study, we assessed the long-term stability of EtG in human hair stored for up to 10 years. A total of 909 samples originally analyzed between 2013 and 2022 were re-tested in 2023 using a previously published and validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. When the results of the old and the new analyses were compared, EtG concentrations showed no significant degradation over time, with more than 80% of the samples displaying matching values when analytical uncertainty was considered. Only a small fraction of samples (4.4%) dropped below the commonly used interpretive threshold for chronic alcohol use (30 pg/mg) after 10 years of storage. These findings provide robust evidence that EtG remains chemically stable in hair under standard storage conditions over a decade, confirming the reliability of archived samples for assessing alcohol use history and expanding the utility of EtG analysis in long-term toxicological and forensic investigations. The demonstrated stability strengthens confidence in hair as a matrix for retrospective substance use evaluation across scientific disciplines.