MING-JANG CHIULue L.-F.Sabbagh M.N.TA-FU CHENChen H.H.Yang S.-Y.2020-11-032020-11-0320191664-5464https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061775514&doi=10.1159%2f000496099&partnerID=40&md5=43a2d0b37718e5b609f76059864e1e81https://scholars.lib.ntu.edu.tw/handle/123456789/519453Background: The stability of Alzheimer's disease (AD) biomarkers in plasma, measured by immunomagnetic reduction (IMR) after long-term storage at -80°C, has not been established before. Method: Ninety-nine human plasma samples from 53 normal controls (NCs), 5 patients with amnestic mild cognitive impairment (aMCI), and 41 AD patients were collected. Each plasma sample was aliquoted and stored as single-use aliquots at -80°C. The baseline measurements for Aβ1-40, Aβ1-42, and total Tau protein (T-Tau) concentrations for each sample were done within 3 months of blood draw by IMR. They are referred to as baseline concentrations. A separate aliquot from each sample was assayed with IMR to assess the stability of the measured analytes during storage at -80°C between 1.1 and 5.4 years. This is referred to as a repeated result. Results: IMR shows that plasma levels of Aβ1-40 and Aβ1-42 exhibit stability over 5-year storage at -80°C and that plasma levels of T-Tau are less stable (approximately 1.5 years). Conclusion: Although the measured concentrations of T-Tau in human plasma may alter during storage, the diagnostic utility of the results are only slightly affected when the product of Aβ1-42 and T-Tau concentrations are used. The results show that the overall agreement between baseline and repeated measurements in the ability of discriminating NCs from aMCI/AD patients is higher than 80%. ? 2019 The Author(s) Published by S. Karger AG, Basel.[SDGs]SDG3amyloid beta protein[1-40]; amyloid beta protein[1-42]; tau protein; aged; Alzheimer disease; Article; assay; blood level; blood sampling; controlled study; diagnostic value; human; magnetism; mild cognitive impairment; priority journal; protein stability; reduction (chemistry); storagejournal article10.1159/0004960992-s2.0-85061775514