Fast, definitive diagnosis of Creutzfeldt-Jakob disease (CJD) is important in assessing patient care options and transmission risks. Real-Time Quakink-Induced Conversion (RT-QuIC) assays of cerebrospinal fluid (CSF) have proven to be valuable in distinguishing  CJD from non-CJD conditions. We have recently described an improved RT-QuIC assay which increases sensitivity and reduces testing time from days to hours. We have also reported initial evidence suggesting that highly accurate CJD diagnoses can be obtained from RT-QuIC analyses of olfactory mucosal (OM) brushings. Both of these promising new adaptations of the RT-QuIC technology require further evaluation and validation using much larger sample sets that are collected and/or tested by multiple laboratories. Thus, we propose a multicenter effort to collect and /or analyze large numbers of additional CSF and OM specimens from both CJD and non-CJD patients. The diagnostic sensitivities and specificities of these new RT-QuIC assays will be compared to other diagnostic indices from these patients. In addition, we plan to have seven major prion disease centers collect and/or provide samples from patients; six centers also are diagnostic laboratories, and will test the same large set of blinded CSF and OM samples. This project should provide a broad-based assessment of the accuracy, robustness and ease of implementation of these new state-of-the-art antemortem CJD diagnostic tests.