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

Abstract

IntroductionAvailable 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). MethodsLot-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. ResultsLimit 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). DiscussionThe Elecsys β-amyloid (1–42) assay has high analytical performance that may improve biomarker-based AD diagnosis.