 Step 1. All eligible patients in the emergency department or the neurological ward will be evaluated for enrollment into the study. On admission, 2 x 7.5ml- EDTA-blood tubes will be drawn during the first routine blood sampling, and 2 x 7.5ml-EDTA-blood tubes on the following routine blood-sampling. Copeptin levels will be assessed in a blinded batch analysis upon completion of the plasma asservation. Measurement will be performed with a new chemiluminescence sandwich immunoassay. 