Department of Lab Medicine, 150819Khoo Teck Puat Hospital, Singapore.
Ann Clin Biochem. 2021 May;58(3):220-229. doi: 10.1177/0004563220986593. Epub 2021 Jan 27.
Lipaemic interference on automated analysers has been widely studied using soy-based emulsion such as Intralipid. Due to the greater adoption of fish oil-based lipid emulsion for total parenteral nutrition in view of improved clinical outcomes, we seek to characterize the optical properties of SMOFlipid 20% (Fresenius Kabi, Bad Homburg, Germany), a fish oil-based emulsion, on the Roche Cobas 6000 chemistry analyser (Roche Diagnostic, Basel, Switzerland).
Various amounts of SMOFlipid were spiked into pooled serums. We plotted Roche Cobas Serum Index Gen.2 Lipaemia Index (L-index) against the amount of SMOFlipid added. We then studied the interference thresholds for aspartate aminotransferase, alanine aminotransferase, albumin and renal panel analytes using SMOFlipid. We subjected five levels of spiked lipaemia to high-speed centrifugation and analysed the specimens pre- and post-centrifugation. To postulate whether fish oil-based lipid emulsion interferes with laboratory results in the clinical setting, we calculated concentrations of SMOFlipid post-lipid rescue therapy and steady-state concentration of a typical total parenteral nutrition regime using pharmacokinetic principles.
SMOFlipid optical behaviour is similar to Intralipid using the Serum Index Gen.2 L-index, with 1 mg/dL of SMOFlipid representing 1 unit of L-index. Manufacturer-stated interference thresholds are accurate for alanine aminotransferase, aspartate aminotransferase, albumin, urea and creatinine. High-speed centrifugation at 60 min 21,100 facilitates the removal of fish oil-based SMOFlipid.
Based on the interference thresholds we verified and pharmacokinetics parameters provided by SMOFlipid manufacturer, total parenteral nutrition may not interfere with chemistry analytes given sufficient clearance, but lipid rescue therapy will interfere. Further studies assessing lipaemic interference on immunoassays are needed.
使用基于大豆的乳液（如 Intralipid）对自动分析仪进行脂血干扰的研究已经很广泛。由于鱼油为基础的脂肪乳剂在改善临床结果方面的应用越来越多，我们试图描述罗氏 Cobas 6000 化学分析仪（罗氏诊断公司，巴塞尔，瑞士）上基于鱼油的 SMOFlipid 20%（费森尤斯卡比，巴德洪堡，德国）的光学特性。
将不同量的 SMOFlipid 加入到混合血清中。我们绘制了罗氏 Cobas 血清指数通用 2 型脂血指数（L-index）与添加的 SMOFlipid 量之间的关系图。然后，我们使用 SMOFlipid 研究了天冬氨酸氨基转移酶、丙氨酸氨基转移酶、白蛋白和肾脏分析物的干扰阈值。我们将五种不同浓度的脂血标本进行高速离心，分析离心前后的标本。为了推测鱼油为基础的脂肪乳剂是否会在临床环境中干扰实验室结果，我们根据药代动力学原理计算了脂质解救治疗后的 SMOFlipid 浓度和典型全胃肠外营养方案的稳态浓度。
SMOFlipid 的光学行为与使用血清指数通用 2 型 L-index 的 Intralipid 相似，每 1 毫克/分升的 SMOFlipid 代表 1 个 L-index 单位。制造商规定的干扰阈值对丙氨酸氨基转移酶、天冬氨酸氨基转移酶、白蛋白、尿素和肌酐是准确的。在 60 分钟 21,100 转/分的高速离心下，有助于去除基于鱼油的 SMOFlipid。
根据我们验证的干扰阈值和 SMOFlipid 制造商提供的药代动力学参数，全胃肠外营养可能不会干扰化学分析物，只要有足够的清除率，但脂质解救治疗会干扰。需要进一步研究免疫分析的脂血干扰。
