University of Maryland School of Medicine, Baltimore, MD, USA.
Clin Biochem. 2010 May;43(7-8):683-90. doi: 10.1016/j.clinbiochem.2010.02.001. Epub 2010 Feb 11.
Galectin-3 is a carbohydrate binding protein that plays many important regulatory roles in inflammation, immunity and cancer. Recent studies indicate that galectin-3 is a mediator of heart failure development and progression. Development of an improved assay for galectin-3 measurement was necessary for appropriate clinical assessment. Key analytical performance characteristics, the reference distribution and association of galectin-3 levels with clinical outcome in heart failure patients are defined.
A two-site ELISA test was examined for measurement matrix, imprecision, limits of blank, detection, and quantitation, as well as linearity, high-dose hook effect, storage stability, cross-reactivity with nine similar compounds, interference with 22 common medications and icterus, lipemia and hemolysis, all in accordance with CLSI guidance. Also the effects of human anti-mouse antibodies and rheumatoid factor on recovery of galectin-3 were investigated. The reference interval was determined for 1092 ostensibly healthy individuals. The association of galectin-3 concentrations with an outcome of mortality was examined in a preliminary analysis of 129 acute decompensated heart failure patients.
Galectin-3 results were equivalent when measured in serum or EDTA plasma. Imprecision studies demonstrated that the total CV was <10% at a low concentration of 6 ng/mL, 7% near the mid-level concentration of 21 ng/mL, and 15% at the high level of 70 ng/mL. The limit of blank was 0.86 ng/mL, the limit of detection was 1.13 ng/mL, and the limit of quantitation was 0.96 ng/mL. The linear measurement range was 0.96-130 ng/mL and there was no high-dose hook at levels up to 500 ng/mL. No cross-reactivity with nine compounds structurally related to galectin-3 and no interference from 22 common medications, icterus or lipemia was found. Hemolysis and presence of human anti-mouse antibodies or rheumatoid factor were found to be potential sources of interference. Samples can be stored for up to 15 days at either 22-28 degrees C or 2-8 degrees C before analysis; measurements are stable after storage at -20 degrees C or -70 degrees C for at least 6 months and through six freeze-thaw cycles. The 90th, 95th and 97.5th percentile of the normal reference interval was 17.6, 20.3 and 22.1 ng/mL, respectively. Galectin-3 in the acute decompensated heart failure patients ranged from 4.0 to 75 ng/mL; using a cutpoint of 22.1 ng/mL in an unadjusted analysis, galectin-3 values were associated with an outcome of death (p=0.035). Galectin-3 is associated with severity of heart failure as indicated by NYHA Class (p-value for trend, 0.017).
This ELISA for galectin-3 measurement demonstrated acceptable analytical characteristics and was associated with mortality in a preliminary unadjusted analysis.
半乳糖凝集素-3 是一种碳水化合物结合蛋白，在炎症、免疫和癌症中发挥着许多重要的调节作用。最近的研究表明，半乳糖凝集素-3 是心力衰竭发展和进展的介质。为了进行适当的临床评估，需要开发一种改进的半乳糖凝集素-3 测量方法。定义了关键分析性能特征、参考分布以及心力衰竭患者中半乳糖凝集素-3 水平与临床结果的相关性。
根据 CLSI 指南，检查了双位点 ELISA 试验的测量矩阵、不精密度、空白限、检测限和定量限，以及线性、高剂量钩状效应、储存稳定性、与 9 种类似化合物的交叉反应、对 22 种常见药物的干扰、黄疸、脂血和溶血。还研究了人抗鼠抗体和类风湿因子对半乳糖凝集素-3 恢复的影响。对 1092 名表面健康个体确定了参考区间。在对 129 名急性失代偿性心力衰竭患者的初步分析中，检查了半乳糖凝集素-3 浓度与死亡率的相关性。
在血清或 EDTA 血浆中测量时，半乳糖凝集素-3 的结果是等效的。不精密度研究表明，在低浓度 6ng/ml 时总 CV<10%，在中间浓度 21ng/ml 时 7%，在高浓度 70ng/ml 时 15%。空白限为 0.86ng/ml，检测限为 1.13ng/ml，定量限为 0.96ng/ml。线性测量范围为 0.96-130ng/ml，在高达 500ng/ml 的水平上没有高剂量钩状效应。与 9 种结构上与半乳糖凝集素-3 相关的化合物无交叉反应，与 22 种常见药物、黄疸或脂血无干扰。发现溶血以及人抗鼠抗体或类风湿因子的存在可能是干扰的来源。在分析前，样品可在 22-28°C 或 2-8°C 下储存长达 15 天；在-20°C 或-70°C 下储存至少 6 个月并经过六次冻融循环后，测量值稳定。正常参考区间的第 90、95 和 97.5 个百分位数分别为 17.6、20.3 和 22.1ng/ml。急性失代偿性心力衰竭患者的半乳糖凝集素-3 范围为 4.0-75ng/ml；在未调整分析中使用 22.1ng/ml 的切点，半乳糖凝集素-3 值与死亡结局相关（p=0.035）。半乳糖凝集素-3 与心力衰竭的严重程度有关，如 NYHA 分级所示（趋势检验的 p 值，0.017）。
这种用于半乳糖凝集素-3 测量的 ELISA 试验表现出可接受的分析特性，并在初步未经调整的分析中与死亡率相关。
