RDW Index / RDWI (Thalassemia vs Iron Deficiency)
RDW index (RDWI): (MCV × RDW) / RBC; a value below ~220 favors beta-thalassemia trait over iron-deficiency anemia.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- MCV
- 65 fL
- RDW
- 14 %
- RBC count
- 5.5 ×10¹²/L
Result: RDW Index 165.5 — favors beta-thalassemia trait (cutoff 220).
The tool opens with these values already filled in. Replace them with your own.
What the result means
- < 220
- Favors beta-thalassemia trait.
- > 220
- Favors iron-deficiency anemia. RDWI = (MCV x RDW) / RBC. A screen, not a diagnosis — confirm with electrophoresis and iron studies.
What you enter
- MCV
- RDW
- RBC count
How this is calculated
Jayabose S, Giamelli J, LevendogluTugal O, et al. Differentiating iron deficiency anemia from thalassemia minor by using an RDW-based index. J Pediatr Hematol Oncol. 1999;21(4):314. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.