Differences between blood and cerebrospinal fluid glial fibrillary Acidic protein levels: The effect of sample stability.

Introduction: Recent evidence has shown that the marker of reactive astrogliosis, glial fibrillary acidic protein (GFAP), has a stronger relationship with cerebral amyloid beta (Aβ) pathology in blood than in cerebrospinal fluid (CSF). This study investigates if pre-analytical treatment of blood and CSF contribute to these unexpected findings.

Methods: Paired CSF and serum samples from 49 individuals (Aβ-negative = 28; Aβ-positive = 21) underwent a series of seven freeze-thaw cycles (FTCs).