Can I get all my iron in one infusion?

At Lambert Medical Practice we use IV iron preparations that deliver 200 mg elemental iron per infusion session. If your calculated iron deficit exceeds 200 mg — which it does for most patients — multiple sessions will be needed, typically given 1–2 weeks apart. Some preparations (such as ferric carboxymaltose) allow higher single doses; your GP will advise the most appropriate protocol based on your iron deficit and clinical situation.

How long between iron infusions?

Our standard protocol spaces infusions approximately two weeks apart. This interval allows the body to begin incorporating the first dose before the second is given, and is generally well tolerated. After completing your planned course of infusions, a blood test is arranged at Week 6 to check that ferritin and haemoglobin have reached target.

Will I need more infusions after my first course?

Possibly — depending on the Week 6 blood test results and whether you have ongoing iron losses (e.g. heavy periods, gastrointestinal bleeding). If your ferritin has not reached target after your initial course, your GP will advise additional infusions. Patients with chronic conditions causing ongoing iron loss may need periodic top-up infusions every 6–12 months.

How Many Iron Infusions Will I Need?

Q: How many iron infusions will I need?

The number of infusions depends on your total iron deficit, calculated using the Ganzoni Formula from your blood results. Each infusion delivers 200 mg of elemental iron. A mild deficit of 400–600 mg requires 2–3 infusions; a moderate deficit of 600–1000 mg requires 3–5; a severe deficit above 1000 mg may need 5 or more. Your GP calculates your specific requirement before treatment begins.

Why There's No Single Answer

One of the most common questions we receive before an iron infusion appointment is "how many sessions will I need?" It's a completely reasonable question — people want to plan their schedule, understand the cost, and know what to expect.

The reason there's no universal answer is that the number of infusions depends on your total iron deficit — and that varies significantly between individuals based on body weight, haemoglobin level, and how depleted your stores are. A 48 kg woman with mild anaemia needs considerably less iron than an 85 kg man with severely low ferritin and significant anaemia.

How the Number of Infusions Is Calculated

At Lambert Medical Practice, we use the Ganzoni Formula to calculate your total iron deficit in milligrams before recommending a treatment plan:

Total Iron Deficit (mg) =

Weight (kg) × (15.0 − Actual Hb g/dL) × 2.4 + 500 mg (iron stores)

Target Hb is set at 15.0 g/dL — a standard repletion target in the Ganzoni Formula. Hb must be divided by 10 to convert from g/L to g/dL. Iron stores of 500 mg are added for adults ≥35 kg to replenish the depot, not just correct Hb.

Once we have the total iron deficit in mg, we divide by the iron delivered per infusion session (200 mg elemental iron) and round up to the nearest whole infusion:

            Number of infusions = ⌈ Total Iron Deficit ÷ 200 ⌉
          

Real Examples: What Different Patients Need

Mild deficiency — 2–3 infusions

Patient: 58 kg woman, Hb 128 g/L (12.8 g/dL), ferritin 9 µg/L

Deficit: 58 × (15.0 − 12.8) × 2.4 + 500 = 307 + 500 = 807 mg

Infusions: ⌈807 ÷ 200⌉ = 5

Moderate anaemia — 5–6 infusions

Patient: 72 kg woman, Hb 100 g/L (10.0 g/dL), ferritin 6 µg/L

Deficit: 72 × (15.0 − 10.0) × 2.4 + 500 = 864 + 500 = 1,364 mg

Infusions: ⌈1364 ÷ 200⌉ = 7

Near-normal Hb, confirmed deficiency — 4–5 infusions

Patient: 53 kg woman, Hb 122 g/L (12.2 g/dL), ferritin 14 µg/L, TSAT 12%

Deficit: 53 × (15.0 − 12.2) × 2.4 + 500 = 356 + 500 = 856 mg

Infusions: ⌈856 ÷ 200⌉ = 5

Severe anaemia — 8+ infusions

Patient: 85 kg man, Hb 88 g/L (8.8 g/dL), ferritin 4 µg/L

Deficit: 85 × (15.0 − 8.8) × 2.4 + 500 = 1,265 + 500 = 1,765 mg

Infusions: ⌈1765 ÷ 200⌉ = 9

These examples illustrate why the number of infusions varies so much between patients — and why a generic "standard two-session course" can significantly under-treat patients with higher deficits or larger body weights.

The Week 6 Blood Test: Why It Matters

After completing your planned infusion course, we arrange a follow-up blood test at Week 6 to check ferritin, haemoglobin, and transferrin saturation. This is not optional — it's the clinical verification that your iron stores have actually reached target.

If your Week 6 ferritin is still below 50–70 µg/L (or your Hb hasn't fully corrected), your GP will advise whether additional infusions are needed. This is particularly relevant for patients with:

Heavy menstrual bleeding (ongoing iron losses during the treatment course)
Inflammatory bowel disease or other conditions affecting iron utilisation
Starting ferritin below 5 µg/L (extremely depleted stores that may require more than one calculation cycle)

Our Treatment Protocol

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Before

Blood results reviewed. Ganzoni calculation performed. Number of infusions confirmed.

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Session 1

First infusion administered. 200 mg elemental iron. 30–60 minutes. Can drive home.

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Sessions 2+

Spaced ~2 weeks apart until calculated course is complete.

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Week 6

Follow-up blood test. Ferritin + Hb checked. Additional sessions advised if needed.

Calculate Your Estimated Number of Infusions

If you already have your blood results, you can estimate the number of infusions you'll need using our free Iron Deficit Estimator. Enter your weight, haemoglobin, ferritin, and TSAT — the tool runs the Ganzoni Formula and gives you an estimated infusion count in under a minute.

Use the Iron Deficit Estimator Iron Infusion Service

Results are estimates based on the Ganzoni Formula. Your GP confirms the treatment plan after reviewing your full blood results and clinical history.

Maintenance Infusions: Do I Need Them Long-Term?

Some patients experience iron deficiency as a recurring condition rather than a one-off episode. This is particularly common in:

Women with heavy menstrual bleeding (menorrhagia) — losing more iron each month than the body can replace through diet
Patients with IBD or coeliac disease — chronic malabsorption means iron stores deplete over time even with normal diet
Post-bariatric surgery patients — reduced stomach acid and bypassed absorptive surface leads to long-term iron deficiency
Regular blood donors — particularly those who donate frequently

For these patients, periodic "maintenance" infusions every 6–12 months may be appropriate, guided by blood tests. Your GP will advise whether this applies to you based on your clinical history and response to initial treatment.

Frequently Asked Questions

The number depends on your total iron deficit, calculated using the Ganzoni Formula from your blood results. Each infusion delivers 200 mg of elemental iron. A deficit of 400–600 mg needs 2–3 infusions; 600–1000 mg needs 3–5; over 1000 mg may need 5 or more. Your GP calculates your specific requirement before treatment begins. Use our Iron Deficit Estimator for a personalised estimate.

Our infusion protocol delivers 200 mg of elemental iron per session. Since most patients have a calculated deficit above 200 mg, multiple sessions are typically required, spaced approximately two weeks apart. Some preparations allow higher single doses in appropriate patients — your GP will advise the best approach for your situation.

Our standard protocol spaces infusions approximately two weeks apart. This interval allows the body to begin incorporating the first dose before the next is given and is generally well tolerated. After completing your course, a blood test at Week 6 confirms whether ferritin and Hb have reached target.

Possibly — this depends on your Week 6 blood test and whether you have ongoing iron losses (heavy periods, gut bleeding, malabsorption conditions). If ferritin hasn't reached target, your GP will advise additional infusions. Patients with chronic conditions may need periodic maintenance infusions every 6–12 months.