Validation of Remote Collection and Quantification of Blood Neurofilament Light in Neurological Diseases

Abstract

Background Promising blood-based biomarkers of neuropathology have emerged with the potential for therapeutic development and disease monitoring. Remote sampling for biomarker assessment could ease the burden of in-person clinical visits and allow for frequent sampling. Here we evaluated a capillary finger-prick collection method for remote quantification of blood neurofilament light (NfL), a blood-based biomarker evident in various neurological disorders, and other exploratory markers of neuronal injury and neuroinflammation (GFAP, tau). Methods Matched samples from venepuncture and finger-prick were collected and processed into plasma and/or serum to directly compare NfL levels from a primary cohort of n=113 neurological patients (n=29 premanifest Huntington's Disease (preHD), n=30 symptomatic Huntington's Disease (HD), n=34 Multiple Sclerosis (MS), n=7 Amyotrophic Lateral Sclerosis (ALS), n=13 Parkinson's Disease (PD)) and n=40 healthy controls. In the discovery cohort, two delayed processing conditions were compared, three- and seven-day delay, simulating ambient shipment. We recruited a confirmatory cohort of n=121 participants (n=64 preHD and n=57 healthy controls from the HD Young Adult Study) to validate the method. Results Capillary NfL and GFAP concentrations were equivalent to those in venous blood serum and plasma. Only NfL remained stable after seven-day processing delay. Capillary NfL replicated disease group differences displayed in venous blood. Findings were replicated in the confirmatory cohort. Conclusions This data supports our finger-prick method for remote collection and quantification of NfL. With the widespread applications for NfL across the spectrum of neurological disorders, this has the potential to transform disease monitoring, prognosis, and therapeutic development within clinical practice and research.