Interlaboratory validation of cerebrospinal fluid α‐synuclein quantification in the diagnosis of sporadic Creutzfeldt‐Jakob disease

Abstract

Introduction Cerebrospinal fluid α-synuclein level is increased in sporadic Creutzfeldt-Jakob disease cases. However, the clinical value of this biomarker remains to be established. In this study, we have addressed the clinical validation parameters and the interlaboratory reproducibility by using an electrochemiluminescent assay. Methods Cerebrospinal fluid α-synuclein was quantified in a total of 188 sporadic Creutzfeldt-Jakob disease and non–Creutzfeldt-Jakob-disease cases to determine sensitivity and specificity values and lot-to-lot variability. Two round robin tests with 70 additional cases were performed in six independent laboratories. Results A sensitivity of 93% and a specificity of 96% were achieved in discriminating sporadic Creutzfeldt-Jakob disease. No differences were detected between lots. The mean interlaboratory coefficient of variation was 23%, and the intralaboratory coefficient of variations ranged 2.70%–11.39%. Overall, 97% of samples were correctly diagnosed. Discussion The herein validated α-synuclein assay is robust, accurate, and reproducible in identifying Creutzfeldt-Jakob disease cases. Thus, it is ready for implementation in the clinical practice to support the diagnosis of Creutzfeldt-Jakob disease.

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“…An innovation of this work is the addition of a-syn in the existing tri-plex quantification platform. This protein is known to be an excellent biomarker for CJD (15) that has been recently validated for its clinical use (40). a-syn is also slightly to moderately decreased in DLB/PDD compared to controls and AD, but with poor discriminatory value (41,42), although we didn't detect significant differences between DLB/PDD cases and the rest of the diagnostic groups.…”

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