Because of the unpredictable course and heterogenous treatment response in multiple sclerosis (MS), there is a need for biomarkers that can reflect disease activity in the clinical follow up of these patients & the Neurofilament light chain (NFL) is considered to be the most promising biomarker in MS patients. The acute and persistent demyelination in MS results in axonal transection and free (NFL) molecules are released in the interstitial space and diffuse into the cerebrospinal fluid (CSF) and into the bloodstream. Serum neurofilament light chain (NFL) is associated with ongoing neuroinflammation and predictive of future neurodegeneration in early MS. Increased levels of serum NFL in early MS stages reflects neuropathological processes driven mainly by ongoing neuroinflammation as indirectly assessed by the accumulation of lesion burden. In addition, serum NFL levels have a stronger association with future development of brain atrophy than with actual or previous brain volume loss. Neurofilament light chain determinations in peripheral blood for detecting axonal damage may represent new possibilities in MS monitoring. The use of plasma for NFL measurement makes this biomarker valuable for clinical studies since sample collection can be performed repeatedly without causing much harm. Most of the reports have been based on results obtained with a commercially-available ELISA that uses two highly-specific, noncompeting monoclonal antibodies to quantify soluble NFL in samples.