According to the most recent recommendations published by the European Society of Cardiology and their focused update, iron deficiency in heart failure is defined as a serum ferritin concentration < 100 μg/L, or 100–299 μg/L with a transferrin saturation (TSAT) < 20%, corresponding to absolute and functional iron deficiency, respectively [4,17,18]. Here, TF is linked to Iron deficiency anemia.