What is a Ferritin Blood Test?

A ferritin blood test measures the level of ferritin in your blood. Ferritin is a protein that stores iron inside your cells. You need iron to make healthy red blood cells. Red blood cells carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organs, including brain development in children.

Too little or too much iron in your body can cause serious health problems if not treated. A ferritin blood test can show how much iron you have stored in your body.

Other names: serum ferritin, serum ferritin level, ferritin serum

What is it used for?

A ferritin blood test is used to help check your iron levels. It can help your health care provider find out if your body is storing the right amount of iron to stay healthy.

The test may also be used to:

  • Help diagnose or rule out conditions related to iron levels, including:
    • Hemochromatosis, having too much iron in your body (also called iron overload)
    • Iron deficiency anemia, having too few red blood cells because you lack iron
    • Liver diseases (much of the ferritin in your body is stored in your liver.)
    • Restless legs syndrome, a tingling or burning feelings in your legs that may be caused by a lack of iron
    • Adult Still disease (also called adult-onset Still disease or AOSD), an uncommon disease that causes joint pain, fever, and rash, often with high ferritin levels
  • Monitor chronic (long-lasting) conditions that may affect your irons levels, such as cancer, kidney disease, and autoimmune diseases

If you’re being treated for problems with iron, the test may be used to check how well the treatment is working.

Why do I need a ferritin blood test?

You may need this test if you have symptoms of iron levels that are too low or too high.

Symptoms of iron levels that are too low include:

  • Shortness of breath
  • Weakness or fatigue
  • Dizziness
  • Arrhythmia (a problem with the rate or rhythm of your heartbeat)

Symptoms of iron levels that are too high can vary and tend to get worse over time. Symptoms may include:

  • Weakness or fatigue
  • Joint pain, commonly in the knees or hands
  • Loss of interest in sex or erectile dysfunction (ED)
  • Abdominal (belly) pain
  • Change in skin color, which may look gray, metallic, or bronze

You may also need this test if the results of other blood tests show that you have low hematocrit or hemoglobin levels.

What happens during a ferritin blood test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

Your health care provider may ask you to fast (not eat or drink) for 12 hours before your test. The test is usually done in the morning. If you have any questions about how to prepare for your test, talk to your health care provider.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Lower than normal ferritin levels may mean you have iron deficiency anemia, or another condition related to low iron levels. Iron deficiency anemia is a common type of anemia, in which your body doesn’t make enough red blood cells. Without treatment it can lead to heart problems, infections, slow growth and brain development in children, and other health issues.

Higher than normal ferritin levels can mean you have too much iron in your body. Conditions that cause increased iron levels include:

  • Liver disease
  • Alcohol use disorder
  • Hemochromatosis 
  • Hyperthyroidism

If your ferritin results are not normal, it does not always mean you have a medical condition that needs treatment. Certain medicines can decrease or increase your ferritin levels. If you have questions about your results, talk with your health care provider.