S100B and Creutzfeldt Jacob disease: For 20 years, the main CSF tests have been the detection of proteins released into the spinal fluid, as the disease process damages glia and neurones; these include 14-3-3, S100b and neurone-specific enolase.13 Over 80% of patients with CJD have abnormalities of these proteins, but importantly, they are not specific to the pathogenesis of CJD; rather, they reflect rapid tissue damage, and therefore, may also be abnormal in many of the mimic conditions.