A ferritin test measures the amount of ferritin in your blood. Ferritin is a blood protein that contains iron. A ferritin test helps your doctor understand how much iron your body stores.

If a ferritin test reveals that your blood ferritin level is lower than normal, it indicates your body's iron stores are low and you have iron deficiency. As a result, you could be anemic.

If a ferritin test shows higher than normal levels, it could indicate that you have a condition that causes your body to store too much iron. It could also point to liver disease, rheumatoid arthritis, other inflammatory conditions or hyperthyroidism. Some types of cancer also can cause your blood ferritin level to be high.

If your doctor suspects you have too much or too little iron in your body, he or she might suggest a ferritin test. The test can diagnose or suggest:

• Iron deficiency anemia
• Hemachromatosis — a condition that causes your body to absorb too much iron from the food you eat
• Liver disease
• Adult Still's disease

Your doctor might also suggest a ferritin test if you've been diagnosed with a disorder that results in too much iron in your body, such as hemochromatosis. Your doctor might use a ferritin test to monitor your condition and guide treatment.

If your blood sample is being tested only for ferritin, you can eat and drink normally before the test. If your blood sample will be used for other tests, you might need to fast for a time before the test. Your doctor will instruct you.

During the ferritin test, a member of your health care team takes a sample of blood by inserting a needle into a vein in your arm. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.

The normal range for blood ferritin is:

• For men, 24 to 336 micrograms per liter
• For women, 11 to 307 micrograms per liter

Lower than normal results

This indicates that you have iron deficiency. You might also be anemic. If your ferritin level is low, your doctor will work to determine the cause.

Higher than normal results

A higher than normal ferritin level can be seen in several conditions. However, diagnosis of these conditions might require additional testing based on your symptoms and physical examination.

• Hemochromatosis
• Porphyria — A group of disorders caused by an enzyme deficiency that affects your nervous system and skin
• Rheumatoid arthritis or another chronic inflammatory disorder
• Liver disease
• Hyperthyroidism
• Leukemia
• Hodgkin's lymphoma
• Multiple blood transfusions
• Alcohol abuse
• Taking too many iron supplements

If your ferritin level is above normal, your doctor might need to evaluate the results with those of other tests to determine next steps.

For specifics about what your ferritin test results mean, talk to your doctor.