TF and chronic kidney disease: De Larochellière et al. [6] identified a potentially correctable cause of anemia in up to 90% of patients: 71% confirmed or possible iron deficiency (serum ferritin < 30 μg/L and/or transferrin saturation < 20%), 18% chronic renal failure, 1% vitamin B12 or folic acid deficiency, and 10% remained unexplained.