Iron Deficiency Calculator - Ganzoni Iron Dose

An iron deficiency calculator is a hematology dosing tool that applies the Ganzoni equation to body weight, current hemoglobin, and target hemoglobin to estimate the cumulative parenteral iron dose in milligrams needed to refill iron stores and reach the target hemoglobin.

• • Size a Parenteral Iron Series: Convert a 70 kg adult with a 9.5 g/dL hemoglobin into a 1,970 mg cumulative dose, then split it into 200 mg infusion sessions.
• • Plan Pregnancy Replacement: Translate a 65 kg pregnant patient with a 10 g/dL hemoglobin into a roughly 1,290 mg dose, with the 12 g/dL pregnancy target.
• • Check Marginal Cost per Gram: Read the iron per 1 g/dL row to see the mg cost of each additional gram of hemoglobin at the entered body weight.

The Ganzoni numbers are most useful in primary care, hematology, and obstetric offices, where the conversation usually moves from a low hemoglobin reading to a parenteral iron prescription in a single visit. When the patient is overweight, the Ganzoni paper recommends ideal body weight, so the Ideal Body Weight Calculator is the natural companion tool for that adjustment.

That calculator uses the Devine, Robinson, and Hamwi formulas to convert actual body weight into the weight the Ganzoni equation expects.

The calculator implements the 1970 Ganzoni equation by multiplying the entered body weight by the hemoglobin gap and by 2.4, then adding the iron stores allowance, and finally splitting the cumulative dose into standard parenteral infusion sessions.

• body weight (kg): The patient's body weight; use ideal body weight when BMI is 30 or above.
• target Hb (g/dL): The hemoglobin to reach; seeded 15 g/dL for men, 13.5 for non-pregnant women, 12 for pregnant women and children.
• actual Hb (g/dL): The current hemoglobin from a complete blood count; below 13 in men, 12 in women, 11 in pregnancy flags anemia.
• 2.4: The Ganzoni conversion factor, from 0.0034 x 0.07 x 1000 = 2.38 rounded to 2.4.
• iron stores (mg): Iron reserve to top up; 15 mg per kg, dropping to 5 mg per kg for BMI 30 and above.

The 2.4 factor combines the 0.34% iron content of hemoglobin, the 7% blood volume fraction, and the 1000 mg per g conversion. The calculator rounds the cumulative dose to the nearest 10 mg so it can be split across the per-session maximum of the chosen product, whether 200 mg iron sucrose vials, 100 mg pediatric iron sucrose ampules, 750 or 1,000 mg ferric carboxymaltose vials, or a 100 mg iron dextran test dose followed by a therapeutic infusion.

According to PubMed - Ganzoni AM, Schweiz Med Wochenschr, 1970, Cumulative parenteral iron dose (mg) = body weight (kg) x (target Hb - actual Hb) (g/dL) x 2.4 + iron stores, with 15 mg/kg iron stores allowance for normal weight adults

According to PubMed - Koch TA et al., Anemia, 2015, The modified Ganzoni formula builds on the 0.34% iron content of hemoglobin, the 7% blood volume fraction, and the 1000 mg per g conversion to return the 2.4 factor the calculator uses

Because the obesity adjustment in the Ganzoni equation fires at BMI 30 and above, the BMI Calculator is the natural companion to confirm the patient's BMI falls in the range that needs the 5 mg/kg iron stores allowance rather than the 15 mg/kg default.

Four ideas drive the Ganzoni equation:

These four ideas cover the math behind the result and the public health threshold behind the input defaults, so the calculator stays useful whether the user is a parent, a pregnant patient, or a clinician planning a series of iron infusions.

For patients whose anemia tracks with chronic kidney disease, the GFR Calculator uses the CKD-EPI equation on the same creatinine and demographic inputs so the Ganzoni dose and the renal function estimate can be reviewed side by side before the infusion series is finalized.

Follow these five steps to turn a hemoglobin reading into a Ganzoni parenteral iron dose and infusion plan:

1. 1 Enter the Body Weight: Type the patient's body weight in kilograms. Use ideal body weight if the patient is overweight (BMI 30+) to avoid over-dosing the iron stores component.
2. 2 Enter the Actual Hemoglobin: Add the patient's current hemoglobin in g/dL from a recent complete blood count. The default of 9.5 g/dL represents a moderate iron deficiency anemia reading.
3. 3 Pick the Patient Category: Choose the patient category that matches the WHO 2011 reference range. The calculator seeds the target hemoglobin field with 15, 13.5, 12, or 12 g/dL.
4. 4 Toggle the Obesity Adjustment: Switch the obesity adjustment to yes when BMI is 30 or higher, which switches the iron stores allowance from 15 mg/kg to 5 mg/kg to match the Ganzoni obesity adaptation.
5. 5 Read the Cumulative Dose and Plan: Read the cumulative iron dose in mg, the iron stores allowance, the hemoglobin gap, the marginal iron cost per 1 g/dL, and the infusion plan, which converts the cumulative dose into 200 mg sessions.

For example, a 60 kg non-pregnant woman with a 10 g/dL hemoglobin and the 13.5 g/dL female target returns a 1,400 mg cumulative dose and a 7-session infusion plan at 200 mg per visit, which is the dose range outpatient iron clinics use for moderate iron deficiency anemia in adult women.

Using a Ganzoni-based iron deficiency calculator gives patients, parents, and clinicians several practical advantages over estimating a parenteral iron dose by hand:

• • Defensible Cumulative Milligram Dose: The 1,970 mg or 1,400 mg result uses the same 2.4 factor and 15 mg/kg iron stores the 1970 Ganzoni paper recommends, matching the reference range in infusion clinic protocols.
• • Built-In Infusion Plan: The plan row splits the cumulative dose into 200 mg standard sessions for adults or 100 mg sessions for children under 35 kg, including the number of visits and the final top-up dose; the per-session amount is a starting suggestion the prescribing clinician adjusts to the labeled maximum for the chosen iron product.
• • Sex- and Pregnancy-Aware Defaults: The patient category select seeds 15 g/dL for men, 13.5 g/dL for non-pregnant women, 12 g/dL for pregnant women, and 12 g/dL for children 5 to 35 kg, mirroring the WHO 2011 cutoffs.
• • Marginal Cost per Gram of Hemoglobin: The iron per 1 g/dL row reports the body weight times 2.4 figure, so the user can see the cost of each extra gram of hemoglobin at the entered body weight.

Most users keep the result open in a browser tab and revisit it after each follow-up hemoglobin, because the cumulative dose shrinks as the actual hemoglobin climbs, which makes the next plan easy to adjust.

Several clinical and methodological factors change what the Ganzoni dose means and how the result should be read:

• • The Ganzoni equation assumes the patient has uncomplicated iron deficiency anemia and a stable hemoglobin volume, so concurrent anemia of inflammation, recent transfusion, active bleeding, or ongoing erythropoietin therapy can move the actual iron requirement off the calculated cumulative dose.
• • The 2.4 conversion factor is an approximation built from the 0.34% iron content of hemoglobin and a 7% blood volume fraction, so very small or very large patients and patients with severe hypoalbuminemia may need a hematology review rather than a direct prescription.

Most published comparisons put the Ganzoni dose within roughly 10 to 20% of the simpler modified formulas, but the original equation is still the one infusion clinic protocols reference when a defensible total milligram dose is needed.

According to World Health Organization - Anaemia fact sheet, WHO 2011 cutoffs define anemia as hemoglobin below 13 g/dL in adult men, 12 g/dL in non-pregnant women, 11 g/dL in pregnant women, and 11 g/dL in children 6 to 59 months