NEFL and nervous system disorder: Accordingly, the aim of this study was to evaluate the influence of varying renal function levels within the non-impaired creatinine clearance range on NfL, GFAP, UCH-L1, and tTAU levels in serum, as well as CSF, of patients with neuroimmunological diseases, especially MS, and other neurological diseases, as well as in somatoform controls.