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TSAT stands for transferrin saturation. It tells what percent of your iron carrier (transferrin) is filled with iron. TSAT helps show if your body has too much usable iron.
Last reviewed: September 2025
Ferritin, TSAT, iron panel, CBC, and more.
What is TSAT?
Transferrin is a protein that carries iron in blood. TSAT is the share of transferrin that is holding iron right now. A higher number means more iron is loaded onto transferrin.
Related reading: High Ferritin · Hemochromatosis Guide
Why TSAT Matters
- Ferritin can go up from inflammation. TSAT helps confirm true iron excess.
- Long-term high TSAT can point to iron overload.
- TSAT is useful to track during treatment.
How to Prepare for the Test
- Follow lab prep rules. Some panels ask for fasting.
- Avoid iron pills before testing unless told otherwise.
- If you were sick, ask if you should wait until you feel better.
Common Result Patterns
- High ferritin + high TSAT: may suggest iron overload
- High ferritin + normal or low TSAT: think inflammation or other causes
- Normal ferritin + high TSAT: ask your clinician about next steps
Next Steps
- Repeat test if results do not match how you feel
- Ask about an iron panel, CBC, and liver enzymes
- If iron overload is likely, your clinician may order an HFE gene test
Need a TSAT check? Order an iron panel →
FAQs
Do I have to fast?
Follow the lab s rules. Some tests do not need fasting, some do.
Can vitamin C change my results?
Vitamin C can help your gut absorb iron. Ask about timing if you take it.
My ferritin and TSAT do not match. What now?
Repeat testing and talk with a clinician. Look at the full picture, not one number.
Educational content only. Not medical advice.