Notes & Sources

• The factor 2.4 derives from the iron content of haemoglobin: blood volume is about 7% of body weight, and haemoglobin contains roughly 3.4 mg of iron per gram. 0.07 × 3.4 × 10 = 2.4.
• Iron stores are conventionally taken as 500 mg in adults weighing 35 kg or more. Below 35 kg, 15 mg/kg is used instead and the target haemoglobin is usually 13 g/dL.
• The result is a total requirement, not a single dose. Divide it according to the maximum single dose of the specific intravenous iron preparation and its dosing interval.
• Ganzoni is known to underestimate requirements in some settings, and several modern preparations are dosed instead by a simple weight and haemoglobin table in their labelling. Where the label provides such a table, follow the label.
• Confirm iron deficiency before replacing. Anaemia of chronic disease responds differently, and parenteral iron given into active infection is generally avoided.