Hemorrhage
Hereditary
Sickle cell disease
Glucose-6-phosphate deficiency
Acquired
Microangiopathic Hemolytic Anemia (MAHA)
Autoimmune hemolytic anemia
Sickle cell disease
Glucose-6-phosphate deficiency
Iron deficiency
Anemia of chronic disease<unk> 
Sideroblastic anemia
Marrow failure
Chemicals (e.g. ETOH)
Radiation
Infection (HIV, parvo)
Vitamin B12/folate deficiency
Drugs (chemo)
HIV
Thalassemia
Hemorrhage
Myelophthistic anemia
Hereditary
Hereditary spherocytosis
Sickle cell disease
Paroxysmal nocturnal hemoglobinuria
Glucose-6-phosphate deficiency