NEFL and chronic kidney disease: In the present study we analysed plasma concentrations of three commonly used biomarkers of neurological disorders; NfL, tau phosphorylated at amino acid 231 (p-Tau231) and GFAP, in a well characterized cohort of patients with CKD stages 3 and 4 (eGFR 15–59 ml/min/1.73 m2) and examined their relationship to measured GFR (mGFR), urine albumin-to-creatinine ratio (U-ACR) and other abnormalities associated with severe CKD.