Do You Have Low Ferritin? Here’s What It Means

You may have heard about the importance of getting enough iron in your diet. This is because your body needs iron to make new red blood cells. If your iron stores get too low, your red blood cell count can drop. This is called iron-deficiency anemia, and it can make you feel tired and sluggish.

But how much iron you eat isn’t the whole story. In order to store iron, your body also relies on a protein called ferritin. A low ferritin level can make you feel the same way as iron-deficiency anemia — even when your iron levels and blood counts are normal. So even though ferritin doesn’t get as much attention as iron, it’s just as important. 

What is ferritin?

Ferritin is a protein that has two main roles in the body:

• It stores iron in the cell. This makes sure that your body has a ready supply of iron available to use.

• It plays a role in the body’s inflammatory response. This means that ferritin increases during inflammation or infection.

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When you have a low ferritin level, it means you also have low levels of iron. But sometimes a low level of ferritin is the earliest sign that your iron stores are running low.

Ferritin isn’t checked as frequently as your iron level or blood counts. So low ferritin can show up as:

• Iron deficiency: Iron deficiency is when your iron stores are low, but you still have a normal amount of red blood cells. 

• Iron-deficiency anemia: Iron-deficiency anemia is when low iron stores lead to a lower number of red blood cells. 

And iron deficiency — both with and without anemia — can lead to similar symptoms.

What are symptoms of low ferritin?

Your body uses iron to help deliver oxygen to the rest of the body — including the brain, the muscles, and the lungs. When ferritin is low, there’s less iron to help carry out that important role. 

So low ferritin can lead to symptoms, such as:  

• Fatigue

• Dizziness

• Headaches

• Trouble breathing

• Weakness 

• Difficulty concentrating

• Changes in mood

Low ferritin is more common in people with certain conditions like:

• Restless leg syndrome

• Breath-holding spells

• Febrile seizures in children 

• Fibromyalgia

• Anxiety or depression

• Attention-deficit hyperactivity disorder (ADHD)

It’s not clear if low ferritin (and iron) causes these conditions for some people, or if it’s related in other ways. And not all people with these conditions have low ferritin. 

What causes low ferritin?

Low ferritin can be caused by anything that lowers the amount of iron in the body. This can happen for a variety of reasons. 

The common causes of low ferritin include: 

• Not getting enough iron in the diet: This is common in vegans and vegetarians because the iron in plant-based foods is harder to absorb.

• Increased use of iron by the body: Young children, pregnant people, and athletes need more iron than other people. Since their bodies use it so rapidly, it can be hard to get enough iron through diet alone.

• Poor absorption of iron: Certain conditions — like inflammatory bowel disease or celiac disease — can make it harder to absorb iron. Also, some medications, like proton pump inhibitors or histamine 2 antagonists can interfere with iron absorption.

• Chronic blood loss: Your blood cells contain a lot of iron. So anything that causes blood loss — like heavy periods, stomach ulcers, or colon cancers — can lead to the loss of iron. 

What is a ferritin blood test, and how does it work?

A ferritin blood test measures the amount of ferritin in your blood. Since ferritin is the protein that stores iron inside your cells, it’s also an indirect way to measure the amount of iron in your body. It’s one of several tests that can help diagnose iron deficiency.

Why would a doctor order a ferritin test? 

A healthcare professional might order a ferritin blood test if they want to check for iron deficiency, or if they’re looking for signs of high inflammation. 

A healthcare professional might want to know if you have low ferritin in the following cases: 

• You have anemia, and they want to find out if iron deficiency is the cause. 

• They’re looking for a cause of a condition that’s associated with low ferritin, like restless leg syndrome or fibromyalgia. 

• You’re having any symptoms of low iron (like fatigue or trouble concentrating).

Sometimes, a healthcare professional might also want to see if you have high ferritin. This can happen if you have a chronic condition like kidney disease or rheumatoid arthritis, or certain kinds of infections or cancers. 

Low ferritin results

A low ferritin result means that you have iron deficiency. Though there’s some debate about the cutoff for a low ferritin level — and it’s different based on age. 

To make matters more confusing, the cutoff is also different based on your other health conditions. This is because inflammation can increase the ferritin level, too. 

Based on the guidelines of the World Health Organization (WHO), a low ferritin level is: 

• Less than 12 ug/dL in a child who’s healthy

• Less than 30 ug/dL in a child with infection or inflammation

For people age 5 years and older, ferritin level is considered low if it’s:

• Less than 15 ug/dL in a person who’s healthy

• Less than 70 ug/dL in a person with infection or inflammation

But some researchers have found that signs of iron deficiency can start showing up even before ferritin drops to that level. So they argue that we should use a different cutoff for low ferritin. Some recommend using 30 ug/dL or even 50 ug/dL as the lower limit of normal even in healthy people. 

High ferritin results

High ferritin results can be a sign that there’s some type of inflammation in the body, or that there’s too much iron in the body. Conditions that lead to high ferritin include:

• Infections

• Cancers

• Chronic diseases

• Obesity

• Chronic alcohol use

• Iron overload, also known as hemochromatosis 

The WHO guidelines for high ferritin level cutoffs break it down by sex and health status. 

For females age 5 years and older, the ferritin level is high if it’s: 

• More than 150 ug/dL in a person who’s healthy

• More than 500 ug/dL in a person with infection or inflammation

For males age 5 years and older, the ferritin level is high if it’s:

• More than 200 ug/dL in a person who’s healthy

• More than 500 ug/dL in a person with infection or inflammation

How is low ferritin treated?

The treatment for low ferritin is iron. The most common form of treatment involves iron pills or liquid taken by mouth. 

Common types of oral iron supplements that are used to treat low ferritin include: 

• Ferrous sulfate (this type is the least expensive but might be more likely to lead to an upset stomach as a side effect) 

• Ferrous gluconate

• Ferrous fumarate

• Polysaccharide iron complex (this type of iron may not be as effective as the others, but it tends to have fewer side effects)

The exact dose usually depends on the degree of iron deficiency. If you have low ferritin, a healthcare professional can tell you what dose of iron would be right for you. 

If your iron deficiency is severe — or if treatment with oral iron supplements hasn’t worked — a healthcare professional might recommend an iron infusion into your vein, known as an intravenous (IV) infusion. There are several types of IV infusions. Some people only need one transfusion to be effective, while others require two or more for treatment. 

In addition to treating the low iron, it’s important to treat the underlying cause of iron deficiency. For example, if the iron deficiency occurs because of low iron in your diet, you’ll want to increase the amount of iron-rich foods you eat. If you have a condition that leads to regular blood loss, like heavy periods, you may need treatment to prevent that blood loss. 

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Written by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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