RDW/MCV Ratio Calculator

What is the RDW/MCV Ratio?

The RDW/MCV ratio, also known as the Green and King index, is a formula calculated from two standard components of a Complete Blood Count (CBC): the Red Cell Distribution Width (RDW-CV) and the Mean Corpuscular Volume (MCV).

Like the Mentzer and Srivastava indices, it is a cost-effective screening tool used to provide an initial clue in distinguishing iron deficiency anemia from beta-thalassemia trait, both of which can present with microcytic (small red blood cell) anemia.

How Does it Help in Diagnosis?

• In iron deficiency, RDW is typically elevated while MCV is low, leading to a higher ratio.
• In thalassemia trait, RDW is often normal while MCV is significantly low, resulting in a lower ratio.
• Using this ratio in conjunction with other indices can increase the predictive accuracy of the initial screening.

Interpreting the Result (Reference Guide)

Limitations and Next Steps

It is critical to remember that this index is a supportive tool, not a definitive diagnosis. It should never be used in isolation to make clinical decisions.

• Results can be affected by co-existing conditions.
• A definitive diagnosis requires iron studies (ferritin, TIBC) and hemoglobin analysis (electrophoresis).
• Always correlate the results with the patient's clinical signs and symptoms.
• Consultation with a hematologist or primary care physician is essential.