Amyloid peptides (Abeta; Aβ) result from cleavage of amyloid precursor protein (APP) by beta and gamma secretase.The 42-amino acid variant, amyloid β peptide 1–42 is a widely accepted key biomarker for Alzheimer’s disease (AD) together with the total tau (T-tau) and phosphorylated tau (P-tau) protein. Diagnostic accuracy of the Aβ 1–42 /Aβ 1–40 ratio in cerebrospinal fluid (CSF)
compared to the concentration of Aβ 1–42 alone was found to be even more significant.
Currently these peptides are analyzed routinely in CSF by immunoassays, but in recent years, liquid chromatography tandem mass spectrometry (LC-MS/MS) has been investigated for the quantification of Aβ1-38, Aβ1-40, and Aβ1–42.
[Blennow 2010, Lewczuk 2015, Lame 2011]