Long-Term Storage Effects on Stability of Aβ1-40, Aβ1-42, and Total Tau Proteins in Human Plasma Samples Measured with Immunomagnetic Reduction Assays

Ming Jang Chiu, Lih Fen Lue, Marwan N. Sabbagh, Ta Fu Chen, H. H. Chen, Shieh Yueh Yang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Background: 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%.

Original languageEnglish
Pages (from-to)77-86
Number of pages10
JournalDementia and Geriatric Cognitive Disorders Extra
Volume9
Issue number1
DOIs
Publication statusPublished - 2019 Jan 1
Externally publishedYes

Keywords

  • Alzheimer's disease
  • Immunomagnetic reduction
  • Plasma biomarkers
  • Storage stability

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Psychiatry and Mental health

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