Here, we assessed the utility of serum neurofilament light chain (NF-L) and tau protein in comparison to CSF markers (NF-L and phosphorylated NF heavy chain (pNF-H), tau, S100B, 14-3-3) and prion conversion assay (real-time quaking induced conversion (RT-QuIC)) for sporadic and genetic CJD. Here, NEFL is linked to Creutzfeldt Jacob disease.