Here, we propose the establishment of a large European and global collaboration to include national surveillance units from both within and outside the European Union. This collaboration will facilitate cooperation between neurologists, epidemiologists and neuropathologists 1) to harmonize the protocols involved in patient documentation, biomaterial sampling/ storage, biomarker testing/assay analysis and data sharing; and 2) to standardise a more precise diagnosis in patients with RPD by analysis of the biochemical markers in the cerebrospinal fluid and blood. We will work on standardisation of tests that are currently available and harmonise their use between centers worldwide. We will define standards for biochemically based diagnosis in most relevant rapid progressive dementia such as CJD and rpAD. As an add-on value, we will define criteria for early differential diagnosis between rapid progressive neurodegenerative or potentially reversible dementia.