What Is Ferritin and Why Does It Matter?

Quick Answer

Ferritin is a blood test that shows your body's stored iron. Haemoglobin tells you whether you are anaemic, but ferritin helps show whether your iron reserves are low.

Full Answer

Ferritin is like your body's iron storage tank.

Haemoglobin is the iron-containing protein in red blood cells that carries oxygen. Ferritin reflects the iron stored in your body for future use.

This is important because a person may have low iron stores even before haemoglobin becomes very low. In that stage, they may feel tired, weak, dizzy, or low in stamina, but the problem may be missed if only haemoglobin is checked.

Useful blood tests for iron deficiency include:

• CBC
• Haemoglobin
• MCV and MCH
• Ferritin
• Serum iron
• TIBC or transferrin saturation
• CRP, if inflammation is suspected

Low ferritin can be seen in people with heavy menstrual bleeding, poor dietary intake, pregnancy, gastrointestinal blood loss, frequent blood donation, or poor absorption.

Ferritin also matters during treatment. You may feel better before ferritin is fully corrected. If you stop iron too early, symptoms can return.