Normal Reference Ranges
Adult
11.5 - 14.5 %
Pediatric
11.5 - 14.5 %
Clinical Significance
Measures the variation in red blood cell size (anisocytosis). Useful for distinguishing iron deficiency anemia (High RDW) from Thalassemia trait (Normal RDW).
Causes of High
- Iron deficiency anemia
- Folate/B12 deficiency
- Recent hemorrhage with reticulocytosis
- Sickle cell disease
Causes of Low
- Normal finding (Uniform cell size)