Background

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).

Method

Various amounts of SMOFlipid were spiked into pooled seras. We plotted Roche Cobas Serum Indices Lipaemic indices(L-index) against the amount of SMOFlipid added. We then studied the interference thresholds for AST, ALT, 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 TPN regime using pharmacokinetic principles.

Results

SMOFlipid optical behaviour is similar to Intralipid using the Serum indices L-index, with 1mg/dL of SMOFlipid representing 1 unit of L-index. Manufacturer stated interference thresholds are accurate for ALT, AST, albumin, urea and creatinine. High speed centrifugation at 60 min 21100G facilitates the removal of fish-oil based SMOFlipid.

Conclusion

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

背景

已使用基于大豆的乳液（如 Intralipid）对自动分析仪的脂血干扰进行了广泛研究。由于更多地采用基于鱼油的脂质乳液来改善临床结果，因此我们试图表征 SMOFLipid 20%（费森尤斯卡比，德国巴特洪堡）的光学特性，这是一种基于鱼油的乳液, 在 Roche Cobas 6000 化学分析仪上 (Roche Diagnostic, Basel, Switzerland)。

方法

将不同量的 SMOFlipid 添加到混合血清中。我们将 Roche Cobas 血清指数脂肪指数（L 指数）与添加的 SMOFlipid 量作图。然后，我们使用 SMOFlipid 研究了 AST、ALT、白蛋白和肾脏面板分析物的干扰阈值。我们对五种水平的加标脂血进行了高速离心，并对离心前后的标本进行了分析。为了假设基于鱼油的脂质乳液是否会干扰临床环境中的实验室结果，我们使用药代动力学原理计算了脂质挽救治疗后 SMOFlipid 的浓度和典型 TPN 方案的稳态浓度。

结果

SMOFlipid 的光学行为与使用血清指数 L 指数的 Intralipid 相似，1mg/dL 的 SMOFlipid 代表 1 个单位的 L 指数。制造商声明的干扰阈值对于 ALT、AST、白蛋白、尿素和肌酐是准确的。21100G 60 分钟高速离心有助于去除鱼油基 SMOFlipid。

结论

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，全胃肠外营养在给予足够清除的情况下可能不会干扰化学分析物，但脂质拯救疗法会干扰。需要进一步研究评估脂血对免疫测定的干扰