Comparing Neurofilament Light Chain Levels in Serum and Plasma.

Neurofilament light chain (NfL) has been suggested as a blood-based biomarker for neuroaxonal injury.1 Blood level of NfL is known to be increased in diverse neurological disorders, including ischemic stroke, demyelinating disease, amyotrophic lateral sclerosis, frontotemporal dementia, and Alzheimer’s disease.2,3 Both serum and plasma NfL levels are associated with smaller hippocampal volume, thinner cerebral cortex, and longitudinal cognitive decline.4,5 Depending on the study, serum or plasma NfL level was analyzed. Previous studies have reported a significant correlation between serum and plasma NfL levels.6,7 However, it is unclear whether such correlation is well maintained under specific conditions such as old age and those who aer amyloid positive. Thus, the objective of this study was to investigate the association between serum and plasma NfL levels according to amyloid positivity.