Faculty Bibliography

The Society of Hair Testing (SoHT) Guidelines for Drug Testing in Hair provide laboratories with recommended best practice guidelines whether they are currently offering drug testing in hair, or plan to offer a hair testing service in the future. The guidelines include reference to recommended sample collection and storage procedures, through sample preparation, pre-treatment and analysis and the use of cut-offs.

An increasing number of toxicology laboratories are choosing to expand the services they offer to include hair testing in response to customer demands. Hair provides the toxicologist with many advantages over conventional matrices in that it is easy to collect, is a robust and stable matrix that does not require refrigeration, and most importantly, provides a historical profile of an individual's exposure to drugs or analytes of interest. The establishment of hair as a complementary technique in forensic toxicology is a direct result of the success of the matrix in medicolegal cases and the wide range of applications. However, before introducing hair testing, laboratories must consider what additional requirements they will need that extend beyond simply adapting methodologies already validated for blood or urine. Hair presents many challenges with respect to the lack of available quality control materials, extensive sample handling protocols and low drug concentrations requiring greater instrument sensitivity. Unfortunately, a common pitfall involves over-interpretation of the findings and must be avoided.

Over the past decade, oral fluid has established itself as a robust testing matrix for monitoring drug use or misuse. Commercially available collection devices provide opportunities to collect and test oral fluid by the roadside and near-patient testing with both clinical and criminal justice applications. One of the main advantages of oral fluid relates to the collection of the matrix which is non-invasive, simple, and can be carried out under direct observation making it ideal for workplace drug testing. Laboratories offering legally defensible oral fluid workplace drug testing must adhere to national and international quality standards (ISO/IEC 17025); however, these standards do not address issues specific to oral fluid testing. The European Workplace Drug Testing Society (EWDTS) recognizes the importance of providing best practice guidelines to organizations offering testing and those choosing to use oral fluid drug testing to test their employees. The aim of this paper is to present the EWDTS guidelines for oral fluid workplace drug testing.

The intent of this study was to review fatalities involving oxycodone in the west of Scotland using a liquid chromatography-electrospray ionization-tandem mass spectrometry method developed for the determination of oxycodone and N- and O-demethylated metabolites in unhydrolyzed postmortem specimens. Ten oxycodone positive postmortem cases were detected, and nine were drug-related fatalities. Five cases were attributed solely to oxycodone intoxication and four to polydrug intoxication. Although there was overlap between blood oxycodone levels in deaths attributed to oxycodone only and those due to polydrug intoxication, lower oxycodone levels (< 1 mg/L) were associated with polydrug intoxication when compared with cases due to oxycodone alone (> 1 mg/L). The role of the parent drug in oxycodone fatalities has been fully studied, but the role of oxycodone metabolites (noroxycodone and oxymorphone) was investigated in this report for the first time. Oxycodone was more commonly detected in blood, urine, and vitreous humor followed by noroxycodone. The ratio between oxycodone and its N-demethylated metabolite was evaluated and found to be useful in determining whether death occurred shortly after drug administration or if there was a significant delay. High parent/metabolite ratios were correlated with short survival times after ingestion. The median ratio of oxycodone/noroxycodone was 2.4 and ranged from 0.7 to 49. Oxycodone prescriptions have risen sharply in Scotland in recent years, and the identification of 10 oxycodone-related deaths in the past 18 months highlights the importance of including this drug in routine laboratory screening and confirmation procedures.

Beta-hydroxybutyrate (BHB) is considered a potential biomarker for alcoholic ketoacidosis (AKA). A robust and sensitive method was developed and validated for the quantitative determination of BHB in postmortem blood and urine using deuterated gamma-hydroxybutyrate as an internal standard. Samples were analyzed by gas chromatography-mass spectrometry following liquid-liquid extraction and silyl derivatization. The limits of detection and lower limits of quantification in blood and urine were 2 and 7 mg/L and 2 and 6 mg/L, respectively. The interday and intraday precision was measured by coefficients of variation for blood and urine and ranged from 1.0 to 12.4% for quality control samples spiked at 50 and 300 mg/L. The linear range of 50-500 mg/L resulted in an average correlation of R(2) > 0.99, and the average extraction recoveries in blood and urine were >or= 82% and >or= 59%, respectively. BHB remains stable in blood spiked at a concentration of 300 mg/L for 15 days when stored within a refrigerator (2-5 degrees C). Postmortem blood and urine samples were analyzed using the validated method for cases where the deceased had a history of chronic alcohol abuse to establish the use of BHB as a potential marker of AKA.

At the annual meeting of the Society of Hair Testing in Vadstena, Sweden in 2006, a committee was appointed to address the issue of guidelines for hair testing and to assess the current status of accreditation amongst laboratories offering drug testing in hair. A short questionnaire was circulated amongst the membership and interested parties. Fifty-two responses were received from hair testing laboratories providing details on the amount and type of hair tests they offered and the status of accreditation within their facilities. Although the vast majority of laboratories follow current guidelines (83%), only nine laboratories were accredited to ISO/IEC 17025 for hair testing. A significant number of laboratories reporting that they were in the process of developing quality systems with a view to accrediting their methods within 2-3 years. This study provides an insight into the status of accreditation in hair testing laboratories and supports the need for guidelines to encourage best practice.