CSF-tau, CSF-Abeta1-42, ApoE-genotype and clinical parameters in the diagnosis of Alzheimer's disease: combination of CSF-tau and MMSE yields highest sensitivity and specificity.

This study evaluated the sensitivity and specificity of the cerebrospinal fluid (CSF) levels of tau-protein, amyloid-beta-peptide 1-42 (Abeta1-42), ApoE-genotype and the degree of cognitive decline as diagnostic markers for Alzheimer's disease (AD). Data was obtained from 105 AD patients and 68 controls. Median CSF-tau levels were increased (512 pg/ml vs. 145 pg/ml, p<0.001) and Abeta1-42-levels were decreased (238.5 pg/ml vs. 310 pg/ml, p<0.001) in AD patients compared to controls. A weak correlation was found between CSF-Abeta1-42 and MMSE score (r=.245). Within all subjects, a correlation of CSF-Abeta1-42 (r=-.337) and CSF-tau (r=.384) with age was found. The combination of CSF-tau levels and MMSE revealed the highest sensitivity (92%) and specificity (87%). In summary, CSF-tau was a useful biological marker to discriminate AD from normal aging, neurological and psychiatric disorders. CSF-Abeta1-42 showed no additional benefit in discriminating patients from controls but might be useful for tracking the severity of the disease.