Health Encyclopedia

Ferritin (Blood)

Does this test have other names?

Serum ferritin level

What is this test?

This test measures how much iron is in your blood.

Ferritin is a protein that stores iron. Red blood cells need iron to form normally and carry oxygen around your body. Other parts of your body, such as your liver, bone marrow, and muscles, also need iron.

Low levels of ferritin lead to iron deficiency anemia, which means you have too few red blood cells. Iron deficiency can come from a poor diet or blood loss, or your body may have trouble absorbing iron from food. It would take an extremely poor diet for a healthy adult to develop a nutritional iron deficiency, but a low iron level is the most common nutritional deficiency in children. Children need extra iron during times of rapid growth.

In adults, low iron levels usually result from chronic blood loss. If you have ulcers or tumors in your gut, intestinal bleeding, or very heavy menstrual periods, you could lose more iron than you take in and develop an iron deficiency. This can also happen if you are pregnant or breastfeeding.

High levels of ferritin can damage your joints, heart, liver, and pancreas. Too much iron is most often caused by an inherited disease called hemochromatosis. Many people with this disease never have any symptoms, especially women who lose iron through menstruation. But men and some women slowly build up excess iron over the years, and they may begin to feel joint and abdominal (belly) pain in their 20s or 30s. Heavy alcohol use increases the amount of absorbed iron.

Iron poisoning occurs when a large amount of iron is taken in all at once. This happens to children who accidentally overdose on iron supplements. 

Why do I need this test?

You may need this test if your doctors suspects that you have low iron levels. Symptoms include:

  • Pale skin

  • Extreme tiredness and dizziness

  • Heavy menstrual cycles

  • Gastrointestinal bleeding

Children who eat a lot of ice, and toddlers and babies who drink too much whole cow's milk may also get this test.

You might also have this test done to check your ferritin level after treatment for iron deficiency.

What other tests might I have along with this test?

Your doctor may also order other blood tests, including:

  • Serum iron level to measure the iron in the liquid part of your blood.

  • Total iron binding capacity, or TIBC, to measure the amount of transferrin in your blood. Transferrin is the protein that transports ferritin from the gut to the cells that need it.

  • Hemoglobin to measure the number of your red blood cells.

  • Complete blood count, or CBC, to evaluate many different qualities of your blood, including the size of cells.

  • HFE gene test to screen for hemochromatosis.

  • Zinc protoporphyrin to measure the part of the hemoglobin that needs iron to carry oxygen. If iron is low, zinc attaches to the protoporphyrin instead.

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.

Results are given in nanograms per milliliter (ng/mL). The normal range for ferritin in your blood serum is:

  • 12 to 300 ng/mL for adult males

  • 10 to 150 ng/mL for adult females

  • 25 to 200 ng/mL for newborns

  • 200 to 600 ng/mL at 1 month old

  • 50 to 200 ng/mL at 2 to 5 months old

  • 7 to 142 ng/mL for children 6 months to 15 years

If your results are lower, it may mean that you have iron-deficiency anemia. Lower levels may also be caused by certain medications. Antacids can cause absorption problems, and nonsteroidal anti-inflammatory drugs can cause blood loss in your gastrointestinal tract.

If your results are higher, it may mean you have:

  • Hyperthyroidism

  • Hemochromatosis

  • Liver disease

  • Inflammatory diseases

  • Cancer, such as leukemia, lymphoma, or breast carcinoma

You may also have higher levels if you are getting iron-replacement therapy or had a recent blood transfusion.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

Eating foods that are high in iron, including meat, leafy green vegetables, and beans, or taking iron supplements can affect your results. Drinking a lot of milk, donating blood frequently, and running long distances regularly can also affect your results.

How do I get ready for this test?

You don't need to prepare for this test.