Comparison of protein concentrations in serum versus plasma from Alzheimer’s patients

Ryan M. Huebinger, Guanghua Xiao, Kirk C. Wilhelmsen, Ramon Diaz-Arrastia, Fan Zhang, Sid E. O'Bryant, Robert C. Barber

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Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, USA.
Department of Academic and Institutional Resources and Technology, University of North Texas Health Science Center, Fort Worth, USA.
Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, USA.
Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, USA.
Departments of Genetics and Neurology, The Carolina Center for Genome Sciences and the Bowles Center for Alcohol Studies, University of North Carolina, Chapel Hill, USA.
Institute for Aging and Alzheimer’s Disease Research, University of North Texas Health Science Center, Fort Worth, USA.

DOI: 10.4236/aad.2012.13007                

Abstract

Background: There is great interest in developing blood-based biomarkers for Alzheimer’s disease (AD); however, there is no consensus as to what blood fraction is most appropriate for analyzing particular markers. The current study provides empirical evidence regarding how blood-based proteins vary depending on whether they are assayed in serum or plasma. Methods: Weanalyzed concentrations of 100 proteins in matched samples of serum and plasma from 39 Caucasian AD participants from the Texas Alzheimer’s Research and Care Consortium bymultiplex immunoassay. Results: Concentrations of 40 proteins were highly correlated (r²≥ 0.75) between plasma and serum while the remaining proteins were moderately to weakly correlated (r²< 0.75). Discussion: Whether plasma vs. serum is assayed can have a large impact on the observed concentration of some proteins, including several proteins that are of great interest to AD pathophysiology. The current findings may explain the significant discrepancies often times reported in the AD biomarker field.

Keywords

Alzheimer’s Disease; Serum Proteins; Plasma Proteins

Conflicts of Interest

The authors declare no conflicts of interest.

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