CSF Samples

CSF samples were provided by the National CJD Research & Surveillance Unit, United Kingdom. These samples are stored at −80 °C, and consent was obtained from the next of kin for their use in research (05/MRE00/67). CSF samples were selected on the basis of having appropriate ethical consent and sufficient volume to ensure that each participant had an adequate volume of CSF for analysis. Each set of CSF samples was sent to each laboratory on dry ice and was analyzed blind to the final diagnosis. The performance of the RT‐QuIC assay was evaluated in an interlaboratory ring trial, where identical CSF samples were analyzed by each of the participating laboratories. Using this approach, it may be possible to identify analytical procedures that affect overall assay performance.