Ganzoni Iron Deficit
Enter patient weight, current and target hemoglobin, and desired iron stores to calculate the total iron deficit in milligrams.
Typically 13–15 g/dL; adjust for sex, comorbidities, or pregnancy.
Commonly 500 mg for adults; consider 300 mg for smaller patients or maintenance.
Total iron deficit
1256 mg
How to Use This Calculator
Collect anthropometric and lab data
Measure weight and hemoglobin. Choose a realistic target hemoglobin based on patient demographics and clinical goals.
Specify iron store replenishment
Default is 500 mg; adjust for maintenance therapy, ferritin goals, or when partial replacement is appropriate.
Plan replacement strategy
Use the calculated deficit to decide between oral and intravenous iron, dose scheduling, and follow-up monitoring.
Formula
Total iron deficit (mg) = Weight (kg) × (Target Hb − Current Hb) × 2.4 + Iron stores (mg)
2.4 accounts for blood volume (0.0034) × 0.7; adjust per institutional preferences if needed.
Full Description
The Ganzoni formula estimates the total iron requirement for replenishing hemoglobin and iron stores in iron deficiency anemia. It guides intravenous iron dosing and ensures adequate repletion beyond symptomatic improvement. Reassess ferritin and transferrin saturation after therapy, recognize ongoing losses (e.g., GI bleeding, heavy menses), and treat underlying causes to prevent recurrence.
Frequently Asked Questions
Why is 500 mg used for iron stores?
Adults generally require 500 mg to replenish stores. Reduce to 300 mg for low body weight or maintenance therapy.
Can I use this for chronic kidney disease patients?
Yes, though dialysis protocols may specify different targets and iron dosing strategies. Coordinate with nephrology guidelines.
What if target hemoglobin is lower?
Adjust the target (e.g., 12 g/dL) for elderly patients or those with limited cardiovascular reserve to avoid overcorrection.
Do I still need ferritin levels?
Yes. Ferritin and transferrin saturation confirm iron deficiency and monitor repletion, especially in inflammatory states where ferritin may be elevated.