Stability of blood-based biomarkers of Alzheimer's disease over multiple freeze-thaw cycles

• Published in: Alzheimer's & dementia : diagnosis, assessment & disease monitoring Vol. 10; no. 1; pp. 448 - 451
• Main Authors: Keshavan, Ashvini, Heslegrave, Amanda, Zetterberg, Henrik, Schott, Jonathan M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 2018; John Wiley & Sons, Inc; Elsevier; Wiley
• Subjects: Alzheimer's disease; Biomarker; Biomarkers; Blood; Blood-Based Biomarkers; Dementia; Freeze-thaw; Immunoassay; Older people; Plasma; Simoa; Variance analysis; Biomarker; Simoa; Freeze-thaw; Blood
• ISSN: 2352-8729; 2352-8729
• DOI: 10.1016/j.dadm.2018.06.001

Freeze-thaw instability may contribute to preanalytical variation in blood-based biomarker studies. We investigated the effects of up to four freeze-thaw cycles on single molecule array immunoassays of serum neurofilament light chain and plasma total tau, amyloid β 1–40 (Aß40), and Aβ 1–42 (Aβ42). Individuals who had peripheral venepuncture during investigation of suspected neurodegenerative disease were recruited. After standardized preprocessing, 200 μL of plasma and serum aliquots were stored at −80°C within 60 minutes. Aliquots underwent one to four freeze-thaw cycles. There was no significant difference across four freeze-thaw cycles for serum neurofilament light chain (n = 12), plasma total tau (n = 11), or plasma Aβ42 (n = 12). For plasma Aβ40 (n = 14), there were significant median reductions by ratios of .96 and .92 at the third and fourth cycles, respectively. Up to four freeze-thaw cycles do not influence single molecule array blood biomarkers of neurofilament light chain, total tau, or Aβ42, with at most minor reductions in Aβ40.