Technical performance of a novel, fully automated electrochemiluminescence immunoassay for the quantitation of beta-amyloid (1-42) in human cerebrospinal fluid

Introduction Available assays for quantitation of the Alzheimer's disease (AD) biomarker amyloid‐beta 1–42 (Aβ [1–42]) in cerebrospinal fluid demonstrate significant variability and lack of standardization to reference measurement procedures (RMPs). We report analytical performance data for the novel Elecsys β‐amyloid (1–42) assay (Roche Diagnostics). Methods Lot‐to‐lot comparability was tested using method comparison. Performance parameters were measured according to Clinical & Laboratory Standards Institute (CLSI) guidelines. The assay was standardized to a Joint Committee for Traceability in Laboratory Medicine (JCTLM) approved RMP. Results Limit of quantitation was <11.28 pg/mL, and the assay was linear throughout the measuring range (200–1700 pg/mL). Excellent lot‐to‐lot comparability was observed (correlation coefficients [Pearson's r] >0.995; bias in medical decision area <2%). Repeatability coefficients of variation (CVs) were 1.0%–1.6%, intermediate CVs were 1.9%–4.0%, and intermodule CVs were 1.1%–3.9%. Estimated total reproducibility was 2.0%–5.1%. Correlation with the RMP was good (Pearson's r, 0.93). Discussion The Elecsys β‐amyloid (1–42) assay has high analytical performance that may improve biomarker‐based AD diagnosis.