Background Glial Fibrillary Acidic Protein (GFAP) levels are shown to be an indicator of neurologic injury in conditions like Traumatic Brain Injury (TBI) and stroke and as a marker of disease progression in neuromuscular disorders such as multiple sclerosis. Plasma GFAP is also implicated in detecting AD pathology, correlating to the clinical stage of the disease. The performance characteristics of the plasma GFAP immunoassay currently being developed on Beckman Coulter Access 2 and DxI 9000 analyzers are described. Methods The prototype GFAP assay is a one-step sandwich assay utilizing an anti-GFAP mouse monoclonal (MAb) antibody/alkaline phosphatase conjugate and paramagnetic particles coated with a complementary anti-GFAP mouse MAb. Sample and reactants are incubated and washed, and then a chemiluminescent substrate is added. The light generated is directly proportional to the GFAP concentration in the sample. The assay time to the first result is ∼30 minutes. Analytical performance evaluation and method comparison across different platforms was performed. 43 EDTA plasma samples, consisting of 19 Alzheimer’s Disease (AD) patient samples and 24 age-matched healthy normal samples, were evaluated. Results The prototype GFAP assay has a targeted analytical measuring range of 1.0 pg/ml to approximately 700.0 pg/ml (up to 10,000 pg/ml). All normal samples were quantified with 90% measuring below 20.0 pg/ml and a low dose coefficient of variation <4.0%. A comparison of the prototype GFAP assay on DxI 9000 and Access 2 analyzers shows a Passing-Bablok slope of 0.94 (R=0.992) and an intercept of 0.37 pg/ml. Concordance analysis shows excellent agreement between the Access 2 and DxI 9000 assays. The dose ratio of the median of AD over the median of normal samples for Access 2 and DxI 9000 is 2.31 and 2.41, respectively, with AD patient median dose values of 14.3 pg/ml and 14.6 pg/mL, respectively, and normal sample median dose values of 6.2 pg/ml and 6.0 pg/mL, respectively. Conclusions The prototype GFAP assay provides fast, highly sensitive, and precise results in an automated immunoassay on the Beckman Coulter Access 2 and DxI 9000 platforms. The prototype plasma GFAP assay holds promise for diagnosing and monitoring various neurodegenerative diseases, including AD.

中文翻译：

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B-244 新型高通量全自动血浆 GFAP 免疫分析的分析性能和方法比较评估


背景 胶质纤维酸性蛋白 (GFAP) 水平被证明是创伤性脑损伤 (TBI) 和中风等疾病中神经损伤的指标，也是多发性硬化症等神经肌肉疾病疾病进展的标志。血浆 GFAP 还参与检测 AD 病理学，与疾病的临床阶段相关。描述了目前在 Beckman Coulter Access 2 和 DxI 9000 分析仪上开发的血浆 GFAP 免疫测定的性能特征。方法原型 GFAP 测定是一种一步夹心测定，利用抗 GFAP 小鼠单克隆 (MAb) 抗体/碱性磷酸酶缀合物和涂有互补抗 GFAP 小鼠 MAb 的顺磁颗粒。孵育并洗涤样品和反应物，然后添加化学发光底物。产生的光与样品中的 GFAP 浓度成正比。获得第一个结果的检测时间约为 30 分钟。进行了不同平台的分析性能评估和方法比较。对 43 份 EDTA 血浆样本进行了评估，其中包括 19 份阿尔茨海默病 (AD) 患者样本和 24 份年龄匹配的健康正常样本。结果 原型 GFAP 测定的目标分析测量范围为 1.0 pg/ml 至约 700.0 pg/ml（高达 10,000 pg/ml）。所有正常样品均经过定量，其中 90% 的测量值低于 20.0 pg/ml，且剂量变异系数较低 <4.0%。在 DxI 9000 和 Access 2 分析仪上对原型 GFAP 测定进行比较，结果显示 Passing-Bablok 斜率为 0.94 (R=0.992)，截距为 0.37 pg/ml。一致性分析显示 Access 2 和 DxI 9000 检测之间具有极好的一致性。 Access 2 和 DxI 9000 的 AD 中值与正常样本中值的剂量比分别为 2.31 和 2.41，AD 患者中值剂量值分别为 14.3 pg/ml 和 14.6 pg/mL，正常样本中值剂量值分别为 6.2 pg/ml 和 6.0 pg/mL。结论 原型 GFAP 测定在 Beckman Coulter Access 2 和 DxI 9000 平台上的自动免疫测定中提供快速、高灵敏度和精确的结果。原型血浆 GFAP 检测有望用于诊断和监测包括 AD 在内的各种神经退行性疾病。