Iron Deficiency Calculator

Review ferritin, serum iron, TIBC, transferrin saturation, and hemoglobin in one worksheet, with a rough Ganzoni iron-deficit estimate and inflammation context when CRP is available.

About the Iron Deficiency Calculator

Iron studies are easiest to misread when ferritin, transferrin saturation, and hemoglobin are looked at in isolation. Ferritin reflects storage iron, serum iron and TIBC help estimate transferrin saturation, and the hemoglobin value shows whether the iron pattern is already associated with anemia. The useful question is usually not "is one number low?" but whether the whole pattern looks more like depleted stores, inflammation, mixed disease, or possible overload.

This calculator keeps those values in one worksheet. It calculates transferrin saturation, stages the result against a simple depletion model, shows a rough inflammation note when CRP is elevated, and estimates a Ganzoni iron deficit only as a planning reference. The result is meant to support interpretation with the CBC, symptoms, bleeding history, inflammation markers, and clinician judgment rather than to act like a treatment order set.

Why Use This Iron Deficiency Calculator?

This page is useful when ferritin alone is not enough. It keeps ferritin, serum iron, TIBC, transferrin saturation, hemoglobin, and optional CRP in one place so the iron pattern can be reviewed as a whole, and it adds a rough Ganzoni estimate without pretending to replace a formal treatment plan.

How to Use This Calculator

  1. Enter your ferritin level — the most important single iron marker
  2. Enter serum iron and TIBC to calculate transferrin saturation
  3. Enter hemoglobin to assess for anemia
  4. Select your sex for sex-specific reference ranges
  5. Optionally enter weight for a rough Ganzoni iron-deficit estimate
  6. Enter CRP if available for inflammation-adjusted interpretation
  7. Review the pattern table as a reference aid, not a stand-alone diagnosis

Formula

Transferrin saturation = (serum iron / TIBC) × 100. Ganzoni iron deficit = weight (kg) × (target hemoglobin − actual hemoglobin) × 2.4 + 500 mg (stores). The stage labels on this page are a simplified depletion model built from ferritin, transferrin saturation, and hemoglobin thresholds.

Example Calculation

Result: TSAT 7.8%, Stage 3 IDA, Iron deficit 1,629 mg

Ferritin of 8 ng/mL is strongly consistent with depleted iron stores. TIBC of 450 is elevated, which fits an iron-deficient pattern, and the calculated transferrin saturation of 7.8% suggests poor iron availability for erythropoiesis. Because hemoglobin is below the usual female threshold, the worksheet labels the pattern as iron deficiency anemia and shows a rough Ganzoni repletion estimate for context.

Tips & Best Practices

Read the Pattern, Not Just One Number

Ferritin is the anchor test for iron stores, but it is not the whole story. Serum iron fluctuates during the day, TIBC reflects transferrin availability, and transferrin saturation summarizes how much circulating iron is actually available. Looking at those together is more useful than relying on one marker in isolation.

Why Inflammation Complicates Ferritin

Ferritin rises as an acute-phase reactant. That means inflammation, infection, liver disease, or malignancy can make ferritin look reassuring even when iron delivery to the marrow is poor. This page uses the optional CRP input only as a flag for that problem, not as a definitive corrected-ferritin rule.

What the Ganzoni Estimate Means

The Ganzoni formula is included because it is a familiar way to estimate total iron needed to correct anemia and replenish stores. It is still only a rough worksheet number. Real replacement decisions depend on the cause of anemia, route of treatment, formulation, tolerance, kidney function, and clinician judgment.

Sources & Methodology

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Methodology

This page treats iron studies as a pattern-recognition worksheet rather than a stand-alone diagnosis. It calculates transferrin saturation from serum iron and TIBC, then compares ferritin, transferrin saturation, and hemoglobin against a simple depletion model so depleted stores, inflammatory patterns, mixed pictures, and possible overload can be reviewed together. If CRP is entered, the page adds only a cautionary inflammation note because ferritin can rise as an acute-phase reactant. If weight and hemoglobin are entered, it also shows the Ganzoni equation as a rough repletion estimate.

The result is not a treatment protocol. Ferritin interpretation still depends on inflammation, liver disease, kidney disease, malignancy, bleeding history, the CBC, and the rest of the workup, and the Ganzoni value is displayed only as a planning reference rather than an iron-order instruction.

Sources

Frequently Asked Questions

What is the most helpful single marker for iron deficiency?

Ferritin is usually the most helpful single marker because very low ferritin strongly supports depleted iron stores. The catch is that ferritin also rises during inflammation, liver disease, and other acute-phase states, so it should be interpreted with transferrin saturation, hemoglobin, and the clinical setting.

How does this page separate iron deficiency from anemia of chronic disease?

The worksheet compares ferritin, TIBC, and transferrin saturation as a pattern. Low ferritin with high TIBC and low transferrin saturation leans toward iron deficiency, while higher ferritin with low iron and low or normal TIBC can fit inflammatory anemia. It is still a reference pattern, not a definitive diagnosis.

What is the Ganzoni formula doing here?

The Ganzoni equation estimates the total iron amount needed to correct anemia and replenish stores: weight × (target hemoglobin − actual hemoglobin) × 2.4 + 500 mg. On this page it is shown only as a rough repletion estimate, not as a dosing order.

Can ferritin look normal when iron deficiency is still present?

Yes. Ferritin can be pushed upward by inflammation, infection, liver disease, or malignancy. That is why a seemingly ordinary ferritin value can still be misleading if transferrin saturation is low or CRP is elevated.

Why does the page show an inflammation note when CRP is high?

Ferritin is an acute-phase reactant, so inflammatory states can make iron stores look better than they really are. The CRP note is there to flag that possibility and encourage broader interpretation, not to produce a validated corrected ferritin diagnosis.

Does this calculator tell me which iron treatment to use?

No. It summarizes the lab pattern and shows a rough iron-deficit estimate, but route, dose, and timing of iron therapy depend on the cause of the deficiency, severity of anemia, tolerance of oral iron, and the full clinical picture.

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