尿道软膏中的丁卡因通过免疫分析法导致安非他命假阳性结果。

Tetracaine from urethral ointment causes false positive amphetamine results by immunoassay.

机构信息

Pharmacology and Toxicology Laboratory, Service of Biochemistry and Molecular Genetics, Biomedical Diagnostic Center (CDB), University of Barcelona, Hospital Clínic, Barcelona, Spain.

Clinical Toxicology Unit, Emergency Department, Hospital Clínic, Barcelona, Spain.

出版信息

Clin Toxicol (Phila). 2021 Jun;59(6):500-505. doi: 10.1080/15563650.2020.1834114. Epub 2020 Oct 28.

DOI:10.1080/15563650.2020.1834114

PMID:33112680

Abstract

BACKGROUND

Amphetamine urine drug screening by immunoassay is prone to cross-react with other compounds leading to false positive results. Tetracaine is a local anesthetic drug used in the clinical setting as an ointment during urinary catheterization. In our laboratory, tetracaine is often detected by gas chromatography-mass spectrometry in the urine of patients admitted in the emergency department with false positive amphetamine results. The objectives of this study were to investigate if there was cross-reactivity to tetracaine in an amphetamine immunoassay and to retrospectively evaluate the potential contribution of tetracaine to false positive amphetamine results.

METHODS

An interference study was conducted using negative urine samples spiked with increasing concentrations of tetracaine hydrochloride and analyzed with the CEDIA Amphetamine/Ecstasy immunoassay. Retrospectively, urine samples of patients which yielded positive amphetamine immunoassay results and were analyzed by gas chromatography-mass spectrometry were reviewed ( = 417). The presence of tetracaine and/or other drugs by gas chromatography-mass spectrometry were gathered.

RESULTS

Tetracaine caused false positive amphetamine results by immunoassay (cut-off 1000 µg/L) with a concentration of above 40 mg/L. Retrospective analysis of all positive amphetamine immunoassay samples showed that in 45 out of the 417 (10.8%) urine samples no amphetamine-like derivative was identified by gas chromatography - mass spectrometry. In 37 out of 45 (82.2%) of these false positive cases tetracaine was detected, of whom 59.5% (22/37) had an estimated tetracaine concentration of ≥40 mg/L.

CONCLUSIONS

This study confirmed the interference of tetracaine in the CEDIA Amphetamine/Ecstasy immunoassay and that tetracaine may have contributed to around 80% of the false positive amphetamine cases in the urine samples of patients admitted to the emergency department at our institution.

摘要

背景

免疫分析法检测苯丙胺类药物尿液容易与其他化合物发生交叉反应，导致假阳性结果。地卡因是一种局部麻醉药物，在临床中用作导尿时的软膏。在我们的实验室中，地卡因经常通过气相色谱-质谱法在因苯丙胺假阳性结果而入院的急诊科患者尿液中检测到。本研究的目的是调查地卡因是否会对苯丙胺免疫分析产生交叉反应，并回顾性评估地卡因对苯丙胺假阳性结果的潜在贡献。

方法

使用含不同浓度盐酸地卡因的阴性尿液样本进行干扰研究，并使用 CEDIA 苯丙胺/摇头丸免疫分析进行分析。回顾性分析所有因苯丙胺免疫分析结果阳性且经气相色谱-质谱分析的患者尿液样本（n=417）。收集地卡因和/或其他药物的存在情况。

结果

地卡因浓度高于 40mg/L 时，会导致免疫分析法出现苯丙胺假阳性结果（截止值为 1000μg/L）。对所有苯丙胺免疫分析阳性样本的回顾性分析显示，在 417 例尿液样本中，有 45 例（10.8%）未通过气相色谱-质谱法鉴定出类似苯丙胺的衍生物。在这 45 例假阳性病例中，有 37 例（82.2%）检测到地卡因，其中 59.5%（22/37）的地卡因浓度估计≥40mg/L。