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What is a ferritin test?
Your body relies on iron in red blood cells to carry oxygen to all its cells.
Without enough iron, your red blood cells will be unable to supply enough oxygen. However, too much iron isn’t good for your body either. Both high and low iron levels may indicate a serious underlying problem.
If your doctor suspects you’re experiencing an iron deficiency or an iron overload, they may order a ferritin test. This measures the amount of stored iron in your body, which can give your doctor an overall picture of your iron levels.
Ferritin isn’t the same thing as iron in your body. Instead, ferritin is a protein that stores iron, releasing it when your body needs it. Ferritin usually lives in your body’s cells, with very little actually circulating in your blood.
The greatest concentrations of ferritin are typically in the cells of the liver (known as hepatocytes) and immune system (known as reticuloendothelial cells).
Ferritin is stored in the body’s cells until it’s time to make more red blood cells. The body will signal the cells to release ferritin. The ferritin then binds to another substance called transferrin.
Transferrin is a protein that combines with ferritin to transport it to where new red blood cells are made. Imagine transferrin as a dedicated taxi for iron.
While it’s important for a person to have normal iron levels, having enough stored iron is important too. If a person doesn’t have enough ferritin, iron stores can deplete quickly.
Knowing whether you have too much ferritin in your blood or not enough can give your doctor clues about your overall iron levels. The more ferritin in your blood, the more stored iron your body has.
Low ferritin levels
Your doctor may order a ferritin test if you have some of the following symptoms associated with low ferritin levels:
- unexplained fatigue
- chronic headaches
- unexplained weakness
- ringing in your ears
- leg pains
- shortness of breath
High ferritin levels
You can also have very high ferritin levels, which can cause unpleasant symptoms as well. Symptoms of excess ferritin include:
Ferritin levels can also increase as a result of damage to your organs, such as the liver and spleen.
The test can also be used to monitor your overall health, particularly if you have an iron-related condition that causes you to have too much or too little iron in your blood.
The ferritin test requires only a small amount of blood to diagnose your ferritin levels accurately.
In some instances, your doctor may ask you not to eat for at least 12 hours before your blood is drawn. According to the American Association for Clinical Chemistry (AACC), the test is more accurate when it’s performed in the morning after you haven’t eaten for a while.
A healthcare professional may apply a band around your arm to make your veins more visible. After wiping your skin with an antiseptic swab, the provider inserts a small needle into your vein to obtain a sample. This sample is then sent to a laboratory for analysis.
You shouldn’t have to take any special precautions before having the blood test.
At-home testing kits are also available. You can purchase the LetsGetChecked test that checks ferritin levels online here.
Your ferritin blood test results are first evaluated to see if your levels are within normal ranges. According to the Mayo Clinic, the typical ranges are:
- 20 to 500 nanograms per milliliter in men
- 20 to 200 nanograms per milliliter in women
Note that not all laboratories have the same results for ferritin levels in the blood. These are standard ranges, but separate labs may have different values. Always ask your doctor for the particular lab’s normal range when determining if your ferritin levels are normal, high, or low.
A lower-than-normal ferritin level can indicate that you have an iron deficiency, which can happen when you don’t consume enough iron in your daily diet.
Another condition that affects iron levels is anemia, which is when you don’t have enough red blood cells for iron to attach to.
Additional conditions include:
Knowing if your ferritin levels are low or normal can help your doctor better determine the cause.
For example, a person with anemia will have low blood iron levels and low ferritin levels.
However, a person with a chronic disease may have low blood iron levels, but normal or high ferritin levels.
Ferritin levels that are too high can indicate certain conditions.
One example is hemochromatosis, which is when your body absorbs too much iron.
Other conditions that cause high iron levels include:
- rheumatoid arthritis
- adult-onset Still’s disease
- type 2 diabetes
- Hodgkin’s lymphoma
- iron poisoning
- frequent blood transfusions
- liver disease, such as chronic hepatitis C
- restless leg syndrome
Ferritin is what’s known as an acute phase reactant. This means that when the body experiences inflammation, ferritin levels will go up. That’s why ferritin levels can be high in people who have liver disease or types of cancer, such as Hodgkin’s lymphoma.
For example, liver cells have stored ferritin. When a person’s liver is damaged, the ferritin inside the cells begins to leak out. A doctor would expect higher than normal ferritin levels in people with these and other inflammatory conditions.
The most common causes of elevated ferritin levels are obesity, inflammation, and daily alcohol intake. The most common causes of genetic-related elevated ferritin levels is the condition hemochromatosis.
If your ferritin test results are high, your doctor will likely order other tests that can provide more insight into the iron levels in your body. These tests include:
- an iron test, which measures the amount of iron circulating in your body
- a total iron binding capacity (TIBC) test, which measures the amount of transferrin in your body
A ferritin blood test isn’t associated with serious side effects because it requires obtaining a small sample of blood. Talk to your provider, however, if you have a bleeding condition or bruise easily.
You can expect some discomfort as your blood is drawn. After the test, rare side effects include:
- excess bleeding
- feeling faint or light-headed
Always notify your medical provider if you experience discomfort that seems out of the norm.