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England & Fraser Index

England & Fraser Index: Discriminant function for microcytic anemia. Negative values point toward Thalassemia, positive toward IDA.

MCV (fL)

RBC (10⁶/µL)

Hb (g/dL)

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Clinical Use

Differentiating iron deficiency anemia (IDA) from beta-thalassemia trait.

Used when microcytosis is present (MCV < 80 fL).

Often cited as more discriminative than the Mentzer Index in some populations.

Section 2

Formula & Logic

Calculation

Index = MCV − RBC − (5 × Hb) − 3.4

Section 3

Pearls/Pitfalls

Interpretation

Value	Likely Diagnosis
Negative (< 0)	Beta-Thalassemia Trait
Positive (> 0)	Iron Deficiency Anemia

Section 4

Evidence Appraisal

Primary Reference

Differentiation of iron deficiency from thalassaemia trait by routine blood-count

England JM et al. • The Lancet. 1973;301(7801):449-452

Last Comprehensive Review: 2026

Related Hematology Tools

Reticulocyte Index

Caprini VTE Risk

Absolute Neutrophil Count

MCV-based Anaemia Algorithm

Shine & Lal Index

Corrected Reticulocyte Count

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