What Is a Ferritin Blood Test?

Just for a moment, think of your body as a kitchen pantry. Most of it is stocked with food you use every day. But you also store items in there as well -- an extra box of pasta or can of beans to have on hand when supplies get low.

Your body stores iron in the same way. It uses some of the iron it gets from food right away to make oxygen in the blood. But it also stores iron for times when there's not enough in your diet.

Iron is stored in a protein called ferritin. And to see how much is stored in your body, your doctor might order a ferritin blood test.

Why Do I Need This Test?

Doctors order a ferritin test if other blood tests point to possible anemia, which can lead to a lack of oxygen in the blood. It can be used to check if there is too much or too little iron in the body. Doctors can also use it to diagnose restless legs syndrome and Still's disease in adults (a rare type of arthritis with fever and rash).

Low iron could be the cause if you're:

You may also have strange cravings for licorice, chalk, dirt, or clay. You may feel a burning sensation on your tongue.

If left unchecked, low levels of iron can cause heart failure (when your heart doesn’t pump blood to your body as well as it should). It can also cause these symptoms:

A ferritin blood test can also help your doctor figure out whether your body is storing too much iron. High levels may point to alcohol abuse, infection, liver disease, rheumatoid arthritis, overactive thyroid, or some types of cancer.

Symptoms of high iron levels vary and can include:

How Should I Prepare?

If ferritin is the only test you're having, you can eat and drink as usual. You may need to fast for other blood tests. Always check with your doctor beforehand.

Think about wearing a shirt with short sleeves so the technician can get to your arm easily.

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What Happens During the Test?

A ferritin test should only take a few minutes. Remember to look away if the sight of blood or a needle makes you dizzy or nauseous.

After cleaning the skin around it, a technician will insert a needle into a vein in your arm. He may wrap an elastic band around the upper part of your arm to make the vein easier to find. Once the right amount of blood is collected, the technician will take off the band and needle and stop the bleeding with a cotton ball or bandage. The blood will be labeled and sent to a lab.

Any Risks with This Test?

Like other routine blood tests, the ferritin test is considered safe. You may feel the following:

What Do the Results Mean?

Depending on the lab, test results normally come back within a day or two.

If your results are lower than normal, you have iron deficiency and possibly anemia. Your doctor may prescribe iron supplements or order more blood tests to figure out the cause.

Higher than normal results mean your body is storing too much iron. Your doctor may adjust your diet or supplements. Since high iron is a symptom of other medical issues, you may have more tests to pinpoint the cause.

WebMD Medical Reference Reviewed by Melinda Ratini, DO, MS on January 10, 2017

Sources

SOURCES:

KidsHealth: "Blood Test: Ferritin (Iron)."

Lab Tests Online: "Ferritin."

Mayo Clinic: "Ferritin test."

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