Calculators · Haematology · Dose

Ganzoni total iron deficit

Also called Ganzoni formula, iron deficit calculator, IV iron dose

Total parenteral iron needed to correct haemoglobin and replenish iron stores, as printed in the iron sucrose (Venofer) SmPC.

kg

Blank = SmPC default: 15 g/dL if ≥35 kg, 13 g/dL if <35 kg.

mg

Blank = SmPC default: 500 mg if ≥35 kg, 15 mg/kg if <35 kg.

Fill 2 more fields to see the result.

Formula and scoring

Iron deficit (mg) = weight (kg) × (target Hb − actual Hb) (g/dL) × 2.4 + storage iron (mg). 2.4 = 0.0034 (iron fraction of Hb) × 0.07 (blood volume / body weight) × 1000 × 10. ≥35 kg: target 15 g/dL, stores 500 mg. <35 kg: target 13 g/dL, stores 15 mg/kg.

Exam and ward pearls

  • With Hb in g/L the factor is 0.24, not 2.4 (CosmoFer SmPC); mixing units gives a ten-fold error.
  • Target Hb and storage iron are editable; blank uses the SmPC defaults (15 g/dL and 500 mg at ≥35 kg).

When not to rely on it

  • Check the maximum single dose, infusion rate and weight rules in the label of the iron product you actually use.
  • Not for iron overload states or anaemia not due to iron deficiency.

Source

  1. Ganzoni AM. Intravenöses Eisen-Dextran: therapeutische und experimentelle Möglichkeiten. Schweiz Med Wochenschr. 1970;100(7):301-3. PMID 5413918
  2. Venofer (iron sucrose) 20 mg/mL solution: Summary of Product Characteristics, section 4.2. electronic medicines compendium (UK). Link
  3. CosmoFer (iron dextran) 50 mg/mL: Summary of Product Characteristics, section 4.2. electronic medicines compendium (UK). Link

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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