Formula
Total iron deficit (mg) = weight (kg) × (target Hb − actual Hb) (g/dL) × 2.4 + iron stores (mg). Stores = 500 mg if ≥35 kg, else 15 mg/kg. Target Hb 15 g/dL (≥35 kg) or 13 g/dL (<35 kg).
Clinical pearls
- The 2.4 factor = blood volume (~7% body weight) × iron content of Hb (0.34%) × 10; it assumes iron deficiency, not other anemia causes.
- Ganzoni tends to underestimate needs, especially in obesity or ongoing loss; many protocols now use simplified fixed doses (e.g. ferric carboxymaltose label table).
- Use the product label for maximum single and weekly doses.
Examples
ganzoni 70 kg hgb 8iron deficit 30 kg child hb 9how much iv iron for a 60 kg woman with hemoglobin 85 g/L target 13
FAQ
How do I calculate the IV iron dose?
The Ganzoni formula: weight × (target Hb − actual Hb) × 2.4 + 500 mg for stores. For 70 kg and Hb 8 g/dL with a target of 15, that is about 1676 mg.
What target hemoglobin is used in the Ganzoni formula?
15 g/dL for patients 35 kg or more, and 13 g/dL for patients under 35 kg; many clinicians choose a lower target such as 13 g/dL.