Ferinject Dose Estimator
Estimate iron requirement using the Ganzoni formula and compare it with a common simplified Ferinject dosing table.
What this Ferinject calculator does
Ferinject (ferric carboxymaltose) is an intravenous iron formulation used to treat iron deficiency when oral iron is not effective, not tolerated, or when rapid repletion is needed. This calculator helps you quickly estimate iron replacement in two ways:
- Ganzoni formula estimate (a classic weight-and-hemoglobin-based method)
- Simplified dosing table estimate (commonly used practical approach)
How the calculation works
1) Ganzoni iron deficit formula
The tool uses:
Total iron deficit (mg) = body weight (kg) × (target Hb − actual Hb in g/dL) × 2.4 + iron stores (mg)
The coefficient 2.4 approximates blood volume and hemoglobin iron content. The stores component is often set around 500 mg in many adult protocols.
2) Simplified Ferinject table approach
A common dosing matrix is:
- If Hb is 10 g/dL: 1500 mg (<70 kg) or 2000 mg (≥70 kg)
- If Hb is 10 g/dL or higher: 1000 mg (<70 kg) or 1500 mg (≥70 kg)
Depending on local labeling, maximum single-dose and weekly limits apply. This page also estimates how many infusion sessions may be needed based on a max single infusion cap.
When this is useful
- Iron deficiency anemia with oral iron intolerance
- Chronic inflammatory conditions with functional iron deficiency
- Pre-operative iron optimization in selected patients
- Chronic kidney disease and heart failure pathways (per specialist guidance)
Important clinical checks before IV iron
- Confirm iron deficiency (ferritin, transferrin saturation, CBC context)
- Rule out active causes of blood loss and investigate underlying disease
- Review hypersensitivity history and prior IV iron reactions
- Monitor for hypophosphatemia risk where relevant
- Re-check labs after treatment to avoid over-replacement
Example
Suppose a 62 kg patient has Hb 9.4 g/dL, target Hb 13 g/dL, and iron stores set to 500 mg:
- Ganzoni deficit = 62 × (13 − 9.4) × 2.4 + 500 = about 1035 mg
- Rounded practical value ≈ 1000 mg
- Simplified table dose for Hb <10 and weight <70 kg = 1500 mg
In real-world practice, the treating clinician decides between formula-based and protocol-based dosing while considering diagnosis, timeline, and safety monitoring.
Final note
Use this Ferinject calculator as a structured starting point—not as an autonomous prescribing tool. Intravenous iron prescribing should always align with regional formulary rules, institutional protocols, and direct clinician judgment.