Mentzer index: iron deficiency vs thalassaemia trait

Haematology

A microcytic anaemia fork from the FBC alone, before the iron studies and haemoglobin electrophoresis come back.

What you enter

FORMULAMentzer = MCV ÷ RBC count; <13 thalassaemia trait, >13 iron deficiency

SourceMentzer WC. Differentiation of iron deficiency from thalassaemia trait. Lancet 1973;1:882ReviewedFormula and thresholds checked against the source on 2026-08-22. If the source updates, this line will say so.