- Children with previously diagnosed anemia (including known iron deficiency anemia). This includes children with marrow failure (aplastic anemia, Fanconi anemia), hemoglobinopathies (sickle cell disease, thalassemia), lead intoxication, sideroblastic anemia, megaloblastic anemia, enzymopathies (G6PD deficiency, pyruvate kinase deficiency), or membranopathies (hereditary spherocytosis).