TF and hydrops fetalis: Current American and European guidelines on HF define ID are defined by the following parameters: serum ferritin < 100 ng/mL or the combination of ferritin between 100−299 ng/mL and transferrin saturation (TSAT) < 20%; however, only European Society of Cardiology (ESC) guidelines recommend screening and treating HF patients for ID regardless of the presence of anemia [18,19].