Evaluate iron studies (ferritin, serum iron, TIBC, transferrin saturation), stage iron depletion, differentiate IDA from anemia of chronic disease, and calculate iron deficit with the Ganzoni formula.
Iron deficiency is the most common nutritional deficiency worldwide, affecting an estimated 2 billion people and causing approximately half of all anemia cases globally. Accurate interpretation of iron studies — ferritin, serum iron, total iron-binding capacity (TIBC), and transferrin saturation — is critical for distinguishing iron deficiency anemia (IDA) from other causes such as anemia of chronic disease (ACD), thalassemia trait, and sideroblastic anemias.
This calculator evaluates your complete iron panel and stages iron depletion using the classical three-stage model: Stage 1 (storage depletion), Stage 2 (iron-deficient erythropoiesis), and Stage 3 (overt iron deficiency anemia). It also calculates transferrin saturation from serum iron and TIBC, applies inflammation-based corrections when CRP is elevated (since ferritin is an acute-phase reactant that rises during inflammation independent of iron stores), and computes the total iron deficit using the Ganzoni formula for IV iron replacement planning.
Understanding the pattern of iron study results is essential because IDA and ACD require fundamentally different treatment approaches. Incorrectly giving iron supplementation to a patient with anemia of chronic disease can cause harm, while failing to identify concurrent iron deficiency in chronic disease leads to untreated anemia and persistent fatigue.
This calculator provides a comprehensive iron panel interpretation that combines ferritin, serum iron, TIBC, and transferrin saturation into an integrated assessment. It differentiates between IDA, ACD, and mixed anemia with a clear reference table, adjusts for inflammation when CRP is provided, and calculates the precise iron deficit for IV replacement using the Ganzoni formula.
Transferrin Saturation = (Serum Iron / TIBC) × 100. Ganzoni iron deficit = Weight (kg) × (Target Hb – Actual Hb) × 2.4 + 500 mg (stores). Three-stage iron depletion: Stage 1 (ferritin <50), Stage 2 (TSAT <20%, ferritin <30), Stage 3 (Hb below sex-specific cutoff).
Result: TSAT 7.8%, Stage 3 IDA, Iron deficit 1,629 mg
Ferritin of 8 ng/mL confirms severely depleted iron stores. TIBC of 450 is elevated (body upregulating iron absorption). Low TSAT of 7.8% indicates impaired iron supply. With Hb 10.2 g/dL below the WHO female threshold, this is Stage 3 iron deficiency anemia requiring repletion.
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Ferritin is the most sensitive and specific single marker for iron deficiency. A ferritin <15 ng/mL is virtually diagnostic of iron deficiency. However, ferritin can be falsely elevated by inflammation, liver disease, and malignancy.
In IDA: low ferritin (<30), high TIBC (>400), low TSAT (<20%). In ACD: elevated ferritin (30–500), low TIBC (<250), low-to-normal TSAT. Soluble transferrin receptor (sTfR) can help differentiate when ferritin is ambiguous.
It calculates total iron replacement needed: Weight (kg) × (Target Hb - Actual Hb) × 2.4 + 500 mg iron stores. It is used to determine IV iron dosing for complete repletion.
Ferritin levels of 30–50 ng/mL, while "normal," may still represent iron insufficiency, especially for women. Many hematologists consider ferritin <50 ng/mL a threshold for symptomatic iron deficiency even without frank anemia.
Yes. Ferritin rises as an acute-phase reactant during infection, inflammation, and malignancy. A "normal" ferritin of 60 in a patient with active inflammation (CRP >5) may actually represent iron deficiency. Adjusted ferritin ≈ measured ferritin / 3 during acute inflammation.
Oral iron (ferrous sulfate 325 mg every-other-day) is first-line for mild-moderate IDA. IV iron is preferred for severe deficiency (Hb <8), intolerance of oral iron, inflammatory bowel disease, CKD on ESAs, or when rapid repletion is needed.