We hypothesize that IV iron leads to changes in oxidative stress, endothelial function, and potential renal damage depending on the iron formulation (related to the generation of “free” or catalytic labile iron) and this may result in more tubular and glomerular injury manifested as increased proteinuria and raised neutrophil gelatinase–associated lipocalin (NGAL) levels in patients with chronic kidney disease (CKD). This evidence concerns the gene LCN2 and chronic kidney disease.