Other explanations offered by the literature refer to increased accumulation of renalase or renalase metabolites as residual renal function (RRF) diminishes, increased production of renalase from extrarenal sites as a reaction to increased catecholamines levels in CKD, or even the cross-reaction of the tests utilized with other substances in uremic blood [30,34]. This evidence concerns the gene RNLS and chronic kidney disease.