Department of Pathology & Immunology, Washington University in St. Louis School of Medicine., St. Louis, MO.
Department of Laboratories, Barnes Jewish Hospital, St. Louis, MO.
J Appl Lab Med. 2021 Sep 1;6(5):1192-1201. doi: 10.1093/jalm/jfab033.
High-throughput fentanyl immunoassays have recently emerged for clinical use, but early reports have demonstrated relatively high false-positive rates. The purpose of this study was to compare 2 immunoassays, the ARK and ARK II fentanyl immunoassays, and to demonstrate the clinical impact of implementing the ARK II assay.
The ARK and ARK II fentanyl assays were performed on a Roche c 502 chemistry analyzer. Positive and negative percentage agreement was assessed for each assay with 112 residual patient specimens relative to liquid chromatography-tandem mass spectrometry (LC-MS/MS). Cross-reactivity was assessed with the primary metabolite, norfentanyl, and analogs acetylfentanyl, acrylfentanyl, and furanylfentanyl. The proportion of specimens that did not confirm was assessed retrospectively from the laboratory information system.
The concordance of the ARK assay was 75% (kappa 0.46, 95%CI 0.28-0.63) and the ARK II was 93% (kappa 0.86, 95%CI 0.76-0.95) with LC-MS/MS. 30 ng/mL of norfentanyl was required for a positive result by ARK and 15 ng/mL by ARK II. Similar cross-reactivity was observed when fentanyl and norfentanyl were both present in the specimen and with fentanyl analogs. After implementing the ARK II assay, the proportion of specimens that did not confirm by LC-MS/MS decreased from 11.7% per month to 2.0% per month.
The ARK II fentanyl immunoassay has improved concordance relative to the original ARK fentanyl immunoassay using LC-MS/MS as the comparator method. Improved analyte specificity resulted in a reduced proportion of clinical samples that do not confirm.
高通量芬太尼免疫分析最近已应用于临床，但早期报告显示其假阳性率相对较高。本研究旨在比较两种免疫分析方法，ARK 和 ARK II 芬太尼免疫分析，并展示实施 ARK II 分析的临床影响。
ARK 和 ARK II 芬太尼分析在罗氏 c 502 化学分析仪上进行。每种分析方法与 112 份相对液相色谱-串联质谱（LC-MS/MS）的剩余患者标本进行阳性和阴性百分比一致性评估。用主要代谢物去甲芬太尼以及类似物乙酰芬太尼、丙烯芬太尼和呋喃芬太尼评估交叉反应性。从实验室信息系统中回顾性评估未确认标本的比例。
ARK 分析的一致性为 75%（kappa 0.46，95%CI 0.28-0.63），LC-MS/MS 的 ARK II 为 93%（kappa 0.86，95%CI 0.76-0.95）。ARK 需 30ng/mL 的去甲芬太尼才能得到阳性结果，而 ARK II 只需 15ng/mL。当标本中同时存在芬太尼和去甲芬太尼以及芬太尼类似物时，观察到类似的交叉反应性。实施 ARK II 分析后，未通过 LC-MS/MS 确认的标本比例从每月 11.7%降至每月 2.0%。
与使用 LC-MS/MS 作为比较方法的原始 ARK 芬太尼免疫分析相比，ARK II 芬太尼免疫分析的一致性有所提高。分析物特异性的提高导致未确认的临床样本比例降低。
