Advancing Clinical Use of Neurofilament Light Chain: Translational Insights From Research to Routine Practice

Neurofilament Light Chain (NfL) has emerged as a promising biomarker for neurological diseases. NfL, a structural component of axons, is released into cerebrospinal fluid (CSF) and blood following neuro-axonal damage. Highly sensitive immunometric assays have enabled its reliable quantification in blood, facilitating non-invasive monitoring. Several studies demonstrated strong correlations between NfL levels and the risk of developing different neurological diseases and, in individuals already living with a neurological disease, with the risk of worsening. However, interpretation is affected by factors like age, BMI, renal function, and comorbidities. NfL is already utilized as a diagnostic and prognostic biomarker in clinical practice, particularly in specialized centers and research settings, although no FDA-cleared assay is currently available for routine use. Recent research has highlighted that NfL may represent the first of a new generation of neurological biomarkers, with many more ready to come, such as glial fibrillary acidic protein (GFAP), further improving diagnostic and prognostic accuracy. Despite its promising role in the landscape of biomarkers, challenges remain to implement NfL in daily clinical practice, including standardization of assays, defining reference values, and ensuring methodological consistency. Addressing these limitations will be essential for integrating NfL into routine clinical practice, ultimately advancing precision medicine in neurology.