Use this simple screening calculator to help differentiate iron deficiency anaemia from beta-thalassaemia trait using CBC values.
How to use this calculator
- Enter the patient’s MCV value in femtolitres (fL).
- Enter the patient’s RBC count in million cells per microlitre, or ×1012/L.
- Click Calculate to get the Mentzer Index and suggested interpretation.
Mentzer Index = MCV ÷ RBC count
Calculator
Your Mentzer Index is:
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Clinical reminder: This calculator is a screening aid only. It does not replace proper diagnostic tests such as serum ferritin, iron studies, haemoglobin electrophoresis/HPLC, or DNA analysis when indicated.
Sensitivity and specificity reminder
Reported performance varies by study population, age group, pregnancy status, and local prevalence of iron deficiency anaemia and thalassaemia trait.
One commonly cited study in pregnant women reported the Mentzer Index sensitivity/specificity as 91% / 83% for iron deficiency anaemia and 83% / 91% for beta-thalassaemia trait.
Use the result together with clinical assessment and confirmatory investigations, especially when the result is borderline or the clinical picture does not fit.