GSTM1 and anemia (phenotype): Higher phos levels were associated with a greater likelihood for anemia in a population with early CKD (eGFR >30 ml/min/1.73 m2) and normal kidney function deducing that every 0.5 mg/dl increase in phos demonstrated a 16% greater likelihood for moderate anemia (defined as Hb <11 g/dl), and serum phos levels more than 3.5 mg/dl were associated with a greater likelihood for moderate anemia19.