<unk>  is a condition of decreased hemoglobin (Hb) concentration compared to age-matched and gender-matched controls.
Males: Hb < 13 g/dL
Non-Pregnant Females: Hb < 12 g/dL
Pregnant-Females: Hb < 11g/dL
Children: Hb <  <11-12 g/dL (depends on age)
Affects 1/3 of the world's population
Most common causes are uterine and GI bleeding
Males: Hb < 13 g/dL
Non-Pregnant Females: Hb < 12 g/dL
Pregnant-Females: Hb < 11g/dL
Children: Hb <  <11-12 g/dL (depends on age)
4 mechanisms:
Loss of RBCs by hemorrhage (e.g. GI bleed, trauma)
Increased destruction (SCD, hemolytic<unk> 
Impaired production (iron deficiency, folate deficiency, B12 deficiency, aplastic<unk> /myelodysplastic syndrome)
Dilutional (rapid IVF infusion)
Anemia
Hemorrhage
Pancytopenia
Hereditary
Leukopenia
Acquired
Polycythemia
Microangiopathic Hemolytic Anemia 