Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden. henrik.zetterberg@clinchem.gu.se. Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden. henrik.zetterberg@clinchem.gu.se. Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK. henrik.zetterberg@clinchem.gu.se. UK Dementia Research Institute at UCL, London, UK. henrik.zetterberg@clinchem.gu.se. Department of Psychiatry and Neurochemistry, Institute of Neuroscience & Physiology, Sahlgrenska Academy, University of Gothenburg, Mölndal, Sweden. kaj.blennow@neuro.gu.se. Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden. kaj.blennow@neuro.gu.se.