Abstract
The NULISAseq CNS Disease Panel has high potential for AD diagnosis, but the comparability of serum vs. plasma remains unclear. We compared its performance on 43 matched serum-plasma pairs from a memory clinic cohort. The panel reproducibly quantified 124 targets (mean CV = 4.9%) with high detectability (mean = 95.7%). Serum-plasma correlations were strong (ρ > 0.7) for 79 targets. 48 targets had significant NULISA Protein Quantification (NPQ) differences, with 32 higher in plasma. Plasma had more erythrocyte-enriched proteins (HBA1, PGK1, SOD1, PRDX6), while serum had more platelet-derived proteins (CD40LG, BDNF, VEGFA, Aβ40). For classical AD biomarkers, serum-plasma correlations were stronger for p-tau, GFAP, and NfL (ρ > 0.9) than for Aβ targets (ρ = 0.594–0.785). Tau levels were higher in plasma; GFAP and NfL were similar, and Aβ peptides were mixed. Twelve targets, along with p-tau217/Aβ42, were linked to AD diagnosis, with plasma generally showing stronger effects. Our results support serum use but suggest plasma performs better for AD using this panel.
Authors and Affiliations
Marissa F. Farinas¹˒²˒³, Yijun Chen⁴, Xuemei Zeng¹˒²˒³, Michel N. Nafash¹˒²˒³, Ann D. Cohen¹˒³, Oscar L. Lopez¹˒³˒⁵, and Thomas K. Karikari¹˒²˒³˒⁶*
¹ Department of Psychiatry, School of Medicine, University of Pittsburgh, 3811 O’Hara Street, Pittsburgh, PA 15213, USA
² Biofluid Biomarker Laboratory, Western Psychiatric Hospital, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
³ Alzheimer’s Disease Research Center, University of Pittsburgh, Pittsburgh, PA 15213, USA
⁴ Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15213, USA
⁵ Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
⁶ UPMC Western Psychiatric Hospital, 3811 O’Hara Street, Pittsburgh, PA 15213, USA
\* Corresponding author: Thomas K. Karikari