1. Extreme RDW Differential

2. RDW in a Nutshell RDW = StD / MCV x 100%
Any increase in the range of blood cell width increases RDW.
But keep in mind there are limits to RBC size on both ends of the distribution
<36FL are generally not counted
RBCs can only get so big

3. Conditions Associated with High RDW
Iron deficiency anemia*
B12 deficiency
Hereditary spherocytosis
Hemolysis
Delta beta thalassemia trait
Usually lack symptoms
ALL* especially with myelotoxic chemo
Cold agglutinin
Hydroxyurea

4. Iron Therapy and RDW

5. Our Patient Normal CBC except for Hb, platelets, retics, RDW Hemolysis
Would absolute RBC # be helpful?

6. Sources Mean corpuscular volume - UpToDate
Importance of RDW value in differential diagnosis of hypochrome anemias.
Clinical Evaluation of RDW - Yonsei Medical Journal