Teuber-Hanselmann S, Rekowski J, Vogelgsang J, et al. - In this multicenter trans-sectional study, researchers assessed the diagnostic performance of cerebrospinal fluid (CSF) and blood Kallikrein-8 (KLK8) for Alzheimer disease (AD) and mild cognitive impairment (MCI) due to AD. Clinical and laboratory information as well as CSF and/or blood serum samples were collected from 237 participants, including 98 patients with mild AD, 21 patients with AD-related MCI, and 118 controls. CSF KLK8's diagnostic precision was as great as that of core CSF biomarkers for AD and even higher than CSF Aβ42 in the case of MCI. Blood KLK8 was an equally powerful MCI discriminator but a little weaker for AD. This is the first study to demonstrate the potential clinical utility of blood and CSF KLK8 as an incipient AD biomarker.