Cerebrospinal fluid biomarkers for diagnosis of Alzheimer's disease: beta-amyloid(1-42), tau, phospho-tau-181 and total protein.

Alzheimer's disease is a chronic progressive neurodegenerative disease and it is the most prevalent type of dementia. Diagnostic means, including neuroimaging methods, are continuously improving. Nevertheless, it is still a challenge to increase the sensitivity and specificity of a diagnosis of Alzheimer's disease. Two diagnostic areas are especially challenging: first, differentiating early stages of Alzheimer's disease from mild cognitive impairment and normal aging; and second, increasing diagnostic specificity especially when similar clinical symptoms are shared by various types of dementia. To date, the analysis of beta-amyloid(1-42), total tau and phospho-tau-181 from cerebrospinal fluid (CSF) are the best biological markers to diagnose Alzheimer's disease and differentiate it from other forms of dementia with a high reliability and validity. This article reviews the use of CSF biomarkers and of putative blood-related markers.