Diagnostic Value of Cerebrospinal Fluid Neurofilament Light Protein in Neurology

Neurofilament light protein (NfL) is elevated in cerebrospinal fluid (CSF) of a number of neurological conditions compared with healthy controls (HC) and is a candidate biomarker for neuroaxonal damage. The influence of age and sex is largely unknown, and levels across neurological disorders have not been compared systematically to date.

To assess the associations of age, sex, and diagnosis with NfL in CSF (cNfL) and to evaluate its potential in discriminating clinically similar conditions. DATA SOURCES: PubMed was searched for studies published between January 1, 2006, and January 1, 2016, reporting cNfL levels (using the search terms neurofilament light and cerebrospinal fluid) in neurological or psychiatric conditions and/or in HC. STUDY SELECTION: Studies reporting NfL levels measured in lumbar CSF using a commercially available immunoassay, as well as age and sex. DATA EXTRACTION AND SYNTHESIS: Individual-level data were requested from study authors. Generalized linear mixed-effects models were used to estimate the fixed effects of age, sex, and diagnosis on log-transformed NfL levels, with cohort of origin modeled as a random intercept. MAIN OUTCOME AND MEASURE: The cNfL levels adjusted for age and sex across diagnoses.