Total morphine is an important urinary marker of heroin use but can also be present from prescriptions or poppy seed ingestion. In specimens with morphine concentrations consistent with poppy seed ingestion (<4,000 ng/mL), 6-acetylmorphine has served as an important marker of illicit drug use. However, as illicit fentanyl has become increasingly prevalent as a contaminant in the drug supply, fentanyl might be an alternative marker of illicit opioid use instead of or in combination with 6-acetylmorphine. The aim of this study was to quantify opiates, 6-acetylmorphine, fentanyl, and fentanyl analogs in 504 morphine-positive (immunoassay 2,000 ng/mL cutoff) urine specimens from workplace drug testing. Almost half (43%) of morphine positive specimens had morphine concentrations below 4,000 ng/mL, illustrating the need for markers to differentiate illicit drug use. In these specimens, fentanyl (22% co-positivity) was more prevalent than 6-acetylmorphine (12%). Co-positivity of 6-acetylmorphine and semi-synthetic opioids increased with morphine concentration, while fentanyl prevalence did not. In 110 fentanyl positive specimens, the median norfentanyl concentration (1,520 ng/mL) was 9.6x higher than the median fentanyl concentration (159 ng/mL), illustrating the possibility of using norfentanyl as a urinary marker of fentanyl use. The only fentanyl analog identified was para-fluorofentanyl (n=50) with results from most specimens consistent with para-fluorofentanyl contamination in illicit fentanyl. The results confirm the use of fentanyl by employees subject to workplace drug testing and highlights the potential of fentanyl and/or norfentanyl as important markers of illicit drug use.

中文翻译：

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芬太尼作为工作场所药物检测吗啡阳性尿液样本中非法药物使用的标志物

总吗啡是海洛因使用的重要尿液标志物，但也可能来自处方或罂粟籽摄入。在吗啡浓度与罂粟籽摄入量一致（<4,000 ng/mL）的样本中，6-乙酰吗啡已成为非法药物使用的重要标志。然而，随着非法芬太尼作为药物供应中的污染物变得越来越普遍，芬太尼可能代替 6-乙酰吗啡或与 6-乙酰吗啡联合使用，成为非法阿片类药物使用的替代标志。本研究的目的是对来自工作场所药物检测的 504 份吗啡阳性（免疫测定 2,000 ng/mL 截止值）尿液样本中的阿片类药物、6-乙酰吗啡、芬太尼和芬太尼类似物进行定量。几乎一半 (43%) 的吗啡阳性样本的吗啡浓度低于 4,000 ng/mL，这说明需要标记物来区分非法药物的使用。在这些样本中，芬太尼（共阳性率为 22%）比 6-乙酰吗啡（12%）更为普遍。 6-乙酰吗啡和半合成阿片类药物的共阳性率随着吗啡浓度的增加而增加，而芬太尼的流行率却没有增加。在 110 份芬太尼阳性样本中，去甲芬太尼中位浓度（1,520 ng/mL）比芬太尼中位浓度（159 ng/mL）高 9.6 倍，说明使用去甲芬太尼作为芬太尼使用尿液标记物的可能性。唯一确定的芬太尼类似物是对氟芬太尼 (n=50)，大多数样本的结果与非法芬太尼中的对氟芬太尼污染一致。结果证实接受工作场所药物检测的员工使用芬太尼，并强调芬太尼和/或去甲芬太尼作为非法药物使用重要标志的潜力。