CBC, peripheral smear, reticulocyte count
Macrocytic anemia (MCV>100 fL), usually moderate to severe
High RDW
Low reticulocyte count
Hypersegmented neutrophils
If severe, low WBC and low platelets
Serum<unk> 
Normal: > 210 pg/mL
Deficiency: <170 pg/mL
Symptomatic patients usually have levels <100 pg/mL
LDH, bilirubin may be elevated
Evaluate for underlying causes and complications
Macrocytic anemia (MCV>100 fL), usually moderate to severe
High RDW
Low reticulocyte count
Hypersegmented neutrophils
If severe, low WBC and low platelets
Normal: > 210 pg/mL
Deficiency: <170 pg/mL
Symptomatic patients usually have levels <100 pg/mL
Vitamin B12 deficiency
Hemorrhage
Vitamin B7 deficiency
Hereditary
Vitamin B9 deficiency
Acquired
Vitamin A deficiency
Microangiopathic Hemolytic Anemia 