HF patients: 1) Stable ambulatory HF patients with (NYHA II) or (NYHA III), with LVEF ≤45%, and elevated NP Iron deficiency anemia: 1) Serum ferritin level <100 ng/mL or between 100 and 300 ng/mL if TSAT<20% 2) Hb <15 g/dL. The gene discussed is GSTM1; the disease is Iron deficiency anemia.