Clinical usefulness of the CSF β-amyloid Aβ1-42/Aβ1-40 ratio for Alzheimer's disease diagnosis: a retrospective study in a Belgian academic hospital.

DEAR EDITOR, Diagnosing Alzheimer’s disease (AD) can sometimes be challenging. In addition to clinical semiology and brain-imaging techniques, much emphasis has been put during the last years on the biological hallmarks of AD. The usual markers measured in cerebrospinal fluid (CSF) are Total-Tau (T-Tau), Phospo-Tau (P-Tau) and β-amyloid 1–42 peptide (Aβ42). The diagnostic performance of these CSF markers is quite acceptable when used and interpreted together [.]