Mentzer Index calculator
Result
15.0
> 13 — Suggests iron deficiency anaemia
Sensitivity ~87%, specificity ~77% for thalassaemia vs. IDA.
How to use it
- 1
Mentzer index = MCV / RBC. From standard FBC. No additional tests needed.
- 2
< 13 → thalassaemia. Thalassaemia: high RBC despite low MCV. IDA: low RBC proportional to low MCV.
- 3
Confirm with Hb electrophoresis. Mentzer is a screening tool — HbA2 elevation (>3.5%) confirms β-thalassaemia trait.
When to use it
- Microcytic anaemia without confirmed iron deficiency
- Low MCV, low Hb: Mentzer quickly flags thalassaemia for Hb electrophoresis.
- Pre-marital / pre-pregnancy
- Both partners thalassaemia trait: 25% risk of thalassaemia major offspring.
- Mediterranean, South Asian, Middle Eastern patients
- Higher prevalence of thalassaemia trait in these populations.
A reference for clinicians and students, not medical advice. A score supports a decision; it does not make one. Check every result against the patient in front of you and your local protocol.
At a glance
- Specialty
- Haematology
- Inputs
- 2
- Type
- Formula
