O3-01-06

Diagnostic performance of the cerebrospinal fluid (CSF) biomarkers β–amyloid peptide (Aβ1–42), total tau protein (tau) and tau phosphorylated at threonine 181 (P–tau181P) remains to be established compared to clinical diagnosis in autopsy–confirmed dementia subjects. A total of 100 CSF samples from demented patients with autopsy–confirmed pathological diagnoses were included. CSF levels of Aβ1–42, tau and P–tau181P were determined with commercially available single parameter ELISA kits (INNOTEST®). Diagnostic accuracy of a biomarker model (using age–corrected CSF levels of Aβ1–42 and P–tau181P) differentiating Alzheimer's disease (AD) from other dementias was 82.7% compared to 81.6% for clinical diagnosis, showing that this biomarker model gives the same information as a whole clinical work–up (including imaging). Using the biomarker–based model in cases with clinically doubtful diagnoses, a correct diagnosis would have been established in 4 of the 6 autopsy–confirmed AD cases and 3 of the 3 autopsy–confirmed cases with other dementias. This study showed the value of biomarkers in differential dementia diagnosis, using the gold standard (pathological diagnosis) as a reference. Diagnostic accuracy of a biomarker–based model is comparable to clinical diagnostic accuracy, and can help in establishing a correct diagnosis in case of doubtful clinical diagnoses.