[New perspectives in the laboratory diagnosis of dementia].

Over the past 10 years, the status of laboratory analysis in dementia has increasingly changed from its use for exclusion diagnoses for secondary causes of dementias to determining positive diagnoses of neurodegenerative dementias. This especially applies to the cerebrospinal fluid diagnosis of Alzheimer's disease (AD). Just a few years ago, a lumbar puncture was advised only with sufficiently founded clinical suspicion and with higher priority for the exclusion of inflammatory causes of cognitive dementias. In contrast, pathologically changed biomarkers in the cerebrospinal fluid have already been indexed as supportive attributes of the diagnosis in the 2007 amended research criteria of AD. The lumbar puncture is therefore increasingly becoming part of the clinical routine diagnosis of demential processes and has, to some extent, far-reaching consequences. In this article, we discuss some of the important aspects.