Analytical validation and clinical performance of a chemiluminescence immunoassay panel for plasma biomarkers in Alzheimer's disease: a preliminary study.
BACKGROUND Alzheimer's disease (AD) poses a growing global health challenge, highlighting the urgent need for reliable and minimally invasive diagnostic tools. This study aimed to develop and comprehensively validate an automated chemiluminescence immunoassay (CLIA) for the simultaneous quantification of six core plasma AD biomarkers: Aβ1-40, Aβ1-42, p-Tau181, p-Tau217, GFAP and NfL. METHODS A fully automated CLIA platform (Shine i2910, Vazyme, China) was utilized for biomarker detection. A total of 87 plasma samples from hospitalized patients with confirmed diagnosis at Beijing Tiantan Hospital were stratified into three cohorts: AD, Other Dementia (OD), and Mild Cognitive Impairment (MCI). The analytical performance of the assay, including precision, accuracy, linearity, and detection limits, was validated in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines (EP15-A3, EP09-A3, EP06-A2, EP17-A2). RESULTS This CLIA panel achieved robust analytical metrics, with within-run coefficient of variation (CV) < 3%, between-run CV < 5%, relative bias < ±10%, and linear correlation coefficient (R2) > 0.99 for all six biomarkers, along with sub-picogram level detection sensitivity. Clinical sample analysis revealed that AD patients had significantly higher plasma concentrations of p-Tau181 and p-Tau217, along with a significantly reduced Aβ1-42/Aβ1-40, compared with OD and MCI patients (p < 0.05). GFAP and NfL concentrations were significantly elevated in both AD and OD patients relative to the MCI patients (p < 0.05), with no significant difference between AD and OD patients. Receiver operating characteristic (ROC) curve analysis demonstrated an area under the curve (AUC) > 0.7 for all biomarkers, supporting auxiliary differential diagnosis of AD and demonstrating the assay's clinical discriminatory ability. CONCLUSION The developed fully automated CLIA platform enables rapid, high-performance quantification of six core plasma AD biomarkers with satisfactory analytical performance. As a single-center exploratory study without matched healthy controls, this study only provides analytical validation and preliminary clinical discriminatory evidence. It offers a cost-effective, minimally invasive alternative for auxiliary AD screening under clinical research conditions, while large multi-center cohorts are required to verify its real-world large-scale screening value.