Interpretation of Iron, TIBC, and Ferritin Panel Results

Key Components and Their Interpretation

The iron, TIBC, and ferritin panel is a comprehensive assessment of iron status that helps diagnose iron deficiency, iron overload conditions, and evaluate overall iron metabolism 1
Serum Iron measures the amount of circulating iron in the blood, with a normal range of 50-175 μg/dL, and low levels suggest iron deficiency while high levels may indicate iron overload 2
Total Iron Binding Capacity (TIBC) reflects the blood's capacity to bind iron with transferrin, with a normal range of 250-370 μg/dL, and elevated TIBC suggests iron deficiency, while decreased TIBC may indicate chronic inflammation, malnutrition, or iron overload 2
Transferrin Saturation (TSAT) is calculated as (serum iron/TIBC) × 100%, with a normal range of 20-50%, and TSAT <20% suggests iron deficiency, while TSAT >50% suggests iron overload conditions like hemochromatosis 1
Ferritin reflects iron stores in the body, with reference ranges of 20-250 μg/L for men and 20-200 μg/L for women, and low ferritin (<30 μg/L) is highly specific for iron deficiency, while high ferritin may indicate iron overload, inflammation, or liver disease 1, 2

A strong indication of iron deficiency is suggested by TSAT <16% AND TIBC >70 μmol/L, with a 93% predictive value, and ferritin <30 μg/L without inflammation 3
A strong indication against iron deficiency is suggested by TSAT ≥22% AND TIBC ≤70 μmol/L, with a 99% predictive value of normal iron status 1
Suspicious for hemochromatosis is indicated by TSAT >45% and ferritin >200 μg/L (females) or >300 μg/L (males) 1, 4

Inflammation can decrease serum iron, increase ferritin, and affect TSAT calculations, potentially masking iron deficiency 1, 2
Timing of testing is important, as TSAT has diurnal variation and recent meals can increase serum iron, and testing should ideally be done in the morning after fasting 1
Ferritin interpretation in inflammation requires consideration of ferritin up to 100 μg/L, which may still be consistent with iron deficiency despite being in the "normal" range 3
Bone marrow examination remains the gold standard for diagnosing iron deficiency when results are unclear and definitive diagnosis is needed 2

For patients receiving IV iron therapy, iron parameters (ferritin, TSAT) should be evaluated 4-8 weeks after the last infusion to avoid interference with the assay 1
In patients with suspected iron overload and elevated ferritin >1,000 μg/L, further evaluation for liver fibrosis and potential cardiac involvement may be warranted 4
In patients with iron deficiency, investigation for underlying causes (blood loss, malabsorption, etc.) should be pursued based on clinical context 3