Iron Deficit (Ganzoni)

Ganzoni Iron Deficit

Parenteral Iron Requirements

Weight (kg)

Actual Hb (g/dL)

Target Hb (g/dL)

The factor 2.4 = 0.0034(iron content of Hb in %) × 0.07(blood volume as % of body weight) × 1000. 500mg represents average iron stores.

Guidelines & Evidence

Verified

Last Review: 2026-07-17

When to Use

Calculation of total iron requirement in patients with Iron Deficiency Anemia (IDA).

Planning parenteral (IV) iron replacement therapy when oral iron is ineffective, not tolerated, or rapid replenishment is required.

Second or third trimester anemia where Hb < 10.5–11.0 g/dL and ferritin < 30 ng/mL.

Pre-operative optimization for patients with scheduled Cesarean sections and known anemia.

Clinical Thresholds in Pregnancy

Iron deficiency is typically defined as Ferritin < 30 ng/mL. In the presence of inflammation (elevated CRP), a threshold of < 100 ng/mL may be used, though this is less specific in the obstetric population.

How it Works

The Ganzoni Formula

Total Iron Deficit (mg) = Body Weight (kg) × (Target Hb - Actual Hb) (g/dL) × 0.24 + Iron Stores (mg)

Parameter Definitions

Target Hb	Typically 15 g/dL (standard Ganzoni) or 12 g/dL (Obstetric modification)
Factor 0.24	0.0034 (Fe content of Hb ≈0.34%) × 0.07 (Blood vol ≈7% of weight) × 1000
Iron Stores	500 mg (if weight > 35 kg)

Weight Selection in Pregnancy

Use pre-pregnancy weight for the calculation. Using actual weight in late pregnancy may lead to iron overestimation/overload due to the significant portion of weight attributed to fetal/placental tissue and edema.

Last Comprehensive Review: 2026-07-17

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Iron Deficit (Ganzoni)

Ganzoni Iron Deficit

When to Use

When to Use

Clinical Thresholds in Pregnancy

How it Works

The Ganzoni Formula

Parameter Definitions

Weight Selection in Pregnancy

Clinical Pearls

Obstetric Considerations

Limitations

Next Steps

Administration Strategy

Safety Warning

The Evidence

Primary Reference

Intravenous iron-dextran: therapeutic and experimental possibilities.

Obstetric Validation

Intravenous iron sucrose v/s oral ferrous fumarate in treatment of anemia in pregnancy.

Origins & History

Dr. Andreas M. Ganzoni

Historical Context

Recent Journal Updates

Iron Deficit (Ganzoni)

Ganzoni Iron Deficit

When to Use

When to Use

Clinical Thresholds in Pregnancy

How it Works

The Ganzoni Formula

Parameter Definitions

Weight Selection in Pregnancy

Clinical Pearls

Obstetric Considerations

Limitations

Next Steps

Administration Strategy

Safety Warning

The Evidence

Primary Reference

Intravenous iron-dextran: therapeutic and experimental possibilities.

Obstetric Validation

Intravenous iron sucrose v/s oral ferrous fumarate in treatment of anemia in pregnancy.

Origins & History

Dr. Andreas M. Ganzoni

Historical Context

Recent Journal Updates