['Renalase is a kidney-origin monoamine oxidase which can degrade catecholamines and regulate blood pressure and cardiovascular function. Although it has been shown that serum renalase level significantly decreases with impaired renal function, it is not clear whether its level is related to different stages of chronic kidney disease (CKD) in patients.', 'Eighty-seven patients with CKD were selected as subjects of this study to investigate the serum renalase and catecholamine (CA) levels by ELISA method, and their relationship with other renal function indicators.', 'Serum levels of renalase and renalase-catecholamine (R/C) ratios were significantly higher in CKD stage 3-5 patients (217.4 ± 103.8 ng/L, 1.00 ± 0.21) than CKD stage 1-2 patients (162.1 ± 40.1 ng/L, 0.82 ± 0.16; P < 0.05), while there was no significant difference between CKD stage 1-2 patients and the normal control group (167.8 ± 69.4 ng/L, 0.88 ± 0.17; P > 0.05). Renalase levels were linearly correlated with catecholamine levels (R (2) = 0.817; P < 0.01). Serum renalase levels were positively correlated with systolic blood pressure (SBP), serum CA, BUN, SCr, UA, and CKD stage (P < 0.05), while negatively correlated with RBC, Hb and estimated GFR (eGFR) (P < 0.05). R/C ratio was positively correlated with SBP, diastolic blood pressure, BUN, SCr, UA, cystatin C, β2 microglobulin, retinol binding protein-4 and CKD stage (P < 0.05), while negatively correlated with RBC, Hb, eGFR and GFR (P < 0.05).'] Is serum renalase related to catecholamine levels and renal function?