The standardization of results on hair testing for drugs of abuse: An interlaboratory exercise in Lombardy Region, Italy

Technical and health governance aspects of the external quality assessment system for classical and new psychoactive substances analysis testing in blood

New psychoactive substances (NPS) are uncontrolled analogues of existing drugs or newly synthesized chemicals that exhibit psychopharmacological effects. Due to their diverse nature, composition, and increasing prevalence, they present significant challenges to the healthcare system and drug control policies. In response, healthcare system laboratories have developed analytical methods to detect NPS in biological samples. As a Regional Reference Centre, the Sicilian CRQ Laboratory (Regional Laboratory for Quality Control) developed and conducted an External Quality Assessment (EQA) study to assess, in collaboration with the Istituto Superiore di Sanità (ISS), the ability of different Italian laboratories to identify NPS and traditional drugs of abuse (DOA) in biological matrices. Two blood samples were spiked with substances from various drug classes, including synthetic cannabinoids, cathinones, synthetic opiates, and benzodiazepines, at concentrations ranging from 2 to 10 ng/mL. The blood samples were freeze-dried to ensure the stability of DOA and NPS. Twenty-two laboratories from the Italian healthcare system participated in this assessment. The information provided by the laboratories during the registration in an in-house platform included a general description of the laboratory, analytical technique, and the chosen panels of analytes. The same platform was employed to collect and statistically analyze the data and record laboratory feedback and comments. The evaluation of the results revealed that the participating laboratories employed three different techniques for analyzing the samples: GC-MS, LC-MS, and immunoenzymatic methods. Approximately 90 % of the laboratories utilized LC-MS techniques. Around 40 % of false negative results were obtained, with the worst results in the identification of 5-chloro AB PINACA. The results showed that laboratories that used LC-MS methods obtained better specificity and sensitivity compared to the laboratories using other techniques. The results obtained from this first assessment underscore the importance of external quality control schemes in identifying the most effective analytical techniques for detecting trace molecules in biological matrices. Since the judicial authorities have not yet established cut-off values for NPS, this EQA will enable participating laboratories to share their analytical methods and expertise, aiming to establish common criteria for NPS identification.

Systematic assessment of different solvents for the extraction of drugs of abuse and pharmaceuticals from an authentic hair pool

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.

Trends in drug testing in oral fluid and hair as alternative matrices

The use of alternative matrices such as oral fluid and hair has increased in the past decades because of advances in analytical technology. However, there are still many issues that need to be resolved. Standardized protocols of sample pretreatment are needed to link the detected concentrations to final conclusions. The development of suitable proficiency testing schemes is required. Finally, interpretation issues such as link to effect, adulteration, detection markers and thresholds will hamper the vast use of these matrices. Today, several niche areas apply these matrices with success, such as drugs and driving for oral fluid and drug-facilitated crimes for hair. Once those issues are resolved, the number of applications will markedly grow in the future.