We recruited 40 adults participants with CKD (stages 3–5) and functional or absolute iron deficiency (SF level < 200 μg/L or transferrin saturation (TS) < 20% or both) who were due to receive therapeutic IV iron on the basis of the inclusion and exclusion criteria and who had not had an iron infusion in the last 6 weeks (Table 1). This evidence concerns the gene TF and chronic kidney disease.