Hart E Dale, Vikingsson Svante, Winecker Ruth E, Evans Amy L, Cone Edward J, Mitchell John M, Hayes Eugene D, Flegel Ronald R
Center for Forensic Science, RTI International, 3040 East Cornwallis Rd., Research Triangle Park, NC 27709, USA.
Behavioral Pharmacology Research Unit, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD 21224, USA.
J Anal Toxicol. 2023 Mar 21;47(2):154-161. doi: 10.1093/jat/bkac066.
The purpose of this study was to compare results from five commercial hair testing laboratories conducting workplace drug testing with regard to bias, precision, selectivity and decontamination efficiency. Nine blind hair specimens, including cocaine-positive drug user specimens (some contaminated with methamphetamine) and negative specimens contaminated with cocaine, were submitted in up to five replicates to five different laboratories. All laboratories correctly identified cocaine in all specimens from drug users. For an undamaged hair specimen from a cocaine user, within-laboratory Coefficients of Variation (CVs) of 5-22% (median 8%) were reported, showing that it is possible to produce a homogenous proficiency testing sample from drug user hair. Larger CVs were reported for specimens composed of blended hair (up to 29%) and curly/damaged hair (19-67%). Quantitative results appeared to be method-dependent, and the reported cocaine concentrations varied up to 5-fold between the laboratories, making interlaboratory comparisons difficult. All laboratories reported at least one positive result in specimens contaminated with cocaine powder, followed by sweat and shampoo treatments. Benzoylecgonine, norcocaine, cocaethylene and hydroxylated cocaine metabolites were all detected in cocaine powder-contaminated specimens. This indicates that current industry standards for analyzing and reporting positive cocaine results are not completely effective at identifying external contamination. Metabolite ratios between meta- or para-hydroxy-cocaine and cocaine were 6- and 10-fold lower in contaminated specimens compared to those observed in cocaine user specimens, supporting their potential use in distinguishing samples positive due to contamination and drug use.
本研究的目的是比较五家进行 workplace drug testing 的商业毛发检测实验室在偏差、精密度、选择性和去污效率方面的结果。九个盲样毛发标本，包括可卡因阳性吸毒者标本（有些被甲基苯丙胺污染）和被可卡因污染的阴性标本，以最多五次重复的方式提交给五个不同的实验室。所有实验室都正确识别了吸毒者所有标本中的可卡因。对于来自可卡因使用者的未受损毛发标本，报告的实验室内变异系数（CVs）为 5 - 22%（中位数 8%），表明从吸毒者毛发中有可能制备出均匀的能力验证样本。对于由混合毛发组成的标本（高达 29%）和卷曲/受损毛发（19 - 67%），报告的 CVs 更大。定量结果似乎取决于方法，各实验室报告的可卡因浓度差异高达 5 倍，使得实验室间比较困难。所有实验室在经可卡因粉末污染、随后进行汗液和洗发水处理的标本中均报告了至少一个阳性结果。在被可卡因粉末污染的标本中均检测到了苯甲酰爱康宁、去甲可卡因、可卡因乙烯酯和羟基化可卡因代谢物。这表明当前分析和报告可卡因阳性结果的行业标准在识别外部污染方面并不完全有效。与在可卡因使用者标本中观察到的相比，污染标本中间羟基或对羟基可卡因与可卡因之间的代谢物比率低 6 倍和 10 倍，这支持了它们在区分因污染和吸毒导致的阳性样本方面的潜在用途。
