TSAT Calculator — Transferrin Saturation (Iron Saturation)

Transferrin Saturation Quick Reference Table

What Is Iron Saturation (Transferrin Saturation)?

Transferrin saturation (TSAT), also called iron saturation, measures what percentage of your blood's transferrin protein is carrying iron. Transferrin is the main iron transport protein — each molecule can bind up to two iron (Fe³⁺) ions.

In a healthy person, about one-third (33%) of transferrin is saturated with iron. The remaining two-thirds stay empty as a reserve for increased iron absorption when needed. TSAT is one of the cheapest and most informative markers for assessing your body's iron balance.

TSAT Formula — How to Calculate Transferrin Saturation

There are two accepted formulas:

Both values must be from the same blood draw. TIBC is more commonly reported on standard lab panels. The factor 70.9 converts transferrin concentration to its iron-binding equivalent.

Normal Transferrin Saturation Ranges

What Does Low TSAT Mean?

A transferrin saturation below the normal range indicates your blood doesn't have enough iron bound to its carrier protein. Common causes:

• Iron-poor diet — insufficient meat, legumes, or fortified foods
• Impaired absorption — celiac disease, inflammatory bowel disease, gastric bypass
• Pregnancy and lactation — increased iron demands deplete stores
• Chronic blood loss — heavy menstruation, GI bleeding, frequent blood donation
• Chronic inflammation — inflammatory conditions can lower serum iron (functional iron deficiency)

Prolonged low TSAT may progress to iron-deficiency anemia. Your doctor may order ferritin and hemoglobin tests to confirm.

What Does High TSAT Mean?

A TSAT above 50% suggests iron overload — more iron is circulating than your body needs. Causes include:

• Hereditary hemochromatosis — genetic condition causing excessive iron absorption
• Excessive iron supplements — taking high-dose iron without medical need
• Repeated blood transfusions — common in thalassemia or chronic anemia treatment
• Liver disease — impaired iron regulation
• Iron-rich diet combined with alcohol — alcohol increases iron absorption

Iron overload (hemochromatosis) can damage the liver, heart, and pancreas over time. If your TSAT is consistently above 45–50%, your doctor may order genetic testing (HFE gene) and a ferritin level to assess iron stores.

TIBC vs. Transferrin — What's the Difference?

TIBC (Total Iron-Binding Capacity) measures how much iron your blood could carry if all transferrin was fully loaded. It's an indirect measure of transferrin. Serum transferrin directly measures the protein concentration in mg/dL. Most standard lab panels report TIBC; some report transferrin directly — both work for calculating TSAT.

When to Get TSAT Tested

• Unexplained fatigue, weakness, or pale skin
• Family history of hemochromatosis
• Monitoring iron therapy effectiveness
• Chronic kidney disease (hemodialysis patients)
• Elevated liver enzymes with unknown cause
• Joint pain with elevated ferritin

How to Improve Low Iron Saturation

• Eat iron-rich foods: red meat, liver, lentils, spinach, fortified cereals
• Pair plant-based iron with vitamin C (citrus, peppers) to boost absorption
• Avoid tea, coffee, and calcium with iron-rich meals (they block absorption)
• Consider iron supplements if diet alone is insufficient (consult your doctor)
• Use cast iron cookware — it increases iron content of acidic foods
• Get a personalized iron-rich meal plan tailored to your nutritional needs