Evaluating finger-prick blood collection for remote quantification of neurofilament light in neurological diseases.

Promising blood-based biomarkers of neuropathology have emerged with potential for therapeutic development and disease monitoring. However, these tools will require specialist tertiary services for integration into clinical management. Remote sampling for biomarker assessment could reduce burden of in-person clinical visits for such tests as well as increasing the sampling frequency and patient geographical outreach. Here, we evaluated a finger-prick blood collection approach for remote quantification of neurofilament light (NfL), a candidate blood-based biomarker evident in various neurological disorders, and other exploratory markers of neuronal injury and neuroinflammation (GFAP, tau). Matched samples from venepuncture and finger-prick were collected and processed into plasma and/or serum to directly compare analyte levels from a multi-disease discovery cohort (n = 54 healthy controls; n = 57 Huntington's disease (HD); n = 34 multiple sclerosis; n = 7 amyotrophic lateral sclerosis; n = 11 Parkinson's disease), and a HD confirmatory cohort (n = 57 healthy controls; n = 64 HD). Two delayed processing conditions were compared, three- and seven-day delay, simulating ambient shipment. Capillary NfL and GFAP concentrations were equivalent to those in venous serum and plasma in the multi-disease discovery cohort and HD confirmatory cohort. Only NfL remained stable after a seven-day processing delay in both venous and capillary serum samples. Using NfL concentrations from capillary blood, we replicated previously published disease group differences measured in venous blood. This data supports our finger-prick approach 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.