NEFL and neurodegenerative disease: In the clinical work-up of suspected neurodegenerative disease, NfL will most likely be of limited value from a differential diagnostic perspective (with the differentiation of typical idiopathic Parkinson's disease from atypical parkinsonian disorders being one potential exception (Hansson et al. 2017)) but could instead be used to determine disease intensity, predict progression or rule out on-going neurodegeneration for cognitive complaints.