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Is my TIBC (Total Iron-Binding Capacity) normal?

Free blood test checker · Standard + longevity-optimal ranges

µg/dL
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What is a normal TIBC level?

TIBC measures the total capacity of transferrin to bind iron in your blood. Optimal levels are 250-450 mcg/dL. TIBC naturally rises when the body is iron-starved (high TIBC = low iron stores) and falls when iron is adequate or excessive (low TIBC). TIBC and transferrin saturation together provide a complete picture of iron transport — more useful than serum iron alone. TIBC is essential for diagnosing the type of anemia or iron disorder.

RangeValues
Standard Reference250–370 µg/dL

What causes abnormal TIBC levels?

High TIBC is caused by iron deficiency anemia, pregnancy (increased iron demands), oral contraceptive use, and hepatitis. Low TIBC is caused by iron overload (hemochromatosis), chronic inflammatory conditions (rheumatoid arthritis, infections), liver disease (cirrhosis reduces transferrin production), malnutrition, and nephrotic syndrome (urinary protein loss).

When should you see a doctor?

See your doctor if TIBC is above 400 µg/dL (suggests significant iron deficiency) or below 200 µg/dL (suggests iron overload or chronic disease). Always interpret TIBC alongside serum iron, ferritin, and transferrin saturation for the complete diagnostic picture.

TIBC and longevity

TIBC is an indirect but valuable window into iron homeostasis, which is increasingly recognized as a longevity-relevant axis. Iron dysregulation — both deficiency and overload — accelerates aging. Iron deficiency impairs oxygen delivery, exercise capacity, and cognitive function. Iron overload drives oxidative damage through Fenton reactions, damaging DNA, lipids, and proteins. Monitoring TIBC alongside ferritin and transferrin saturation helps maintain iron in the optimal "Goldilocks zone."

Where to get a TIBC test

Labcorp Anemia Panel$79

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Related biomarkers

These biomarkers are often tested alongside TIBC for a more complete picture.

Iron
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Ferritin
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TSAT
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Hemoglobin
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Frequently asked questions

What is a normal TIBC level?
Normal TIBC is 250-370 µg/dL. Above 400 µg/dL strongly suggests iron deficiency. Below 200 µg/dL may indicate iron overload (hemochromatosis), chronic disease, or liver dysfunction.
Why does TIBC go up when iron is low?
TIBC measures how much iron your transferrin proteins can carry. When iron stores are depleted, the liver produces more transferrin to capture every available iron molecule — this raises TIBC. Think of it as your body casting a wider net for a scarce resource.
How do TIBC, iron, and ferritin relate?
These three tests together paint the complete iron picture. Ferritin reflects stored iron, serum iron reflects circulating iron, and TIBC reflects transport capacity. In iron deficiency: ferritin low, iron low, TIBC high. In iron overload: ferritin high, iron high, TIBC low.

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Sources: Reference ranges based on AHA/ACC, ADA, and AACE clinical guidelines. Biological variation data from Ricos/Westgard database. Longevity-optimal ranges reflect targets used by preventive and functional medicine practitioners.

Last reviewed: April 2026. This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider about your specific results.

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