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.
What Is Ferritin?
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. According to the Mayo
Medical Laboratories, ferritin contains 20 percent iron. 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.
Purpose of a Ferritin Test
If you don’t have enough ferritin in your blood or you have
too much, it 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
- 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:
- stomach pain
- heart palpitations or chest pains
- unexplained weakness
- joint pain
- unexplained fatigue
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.
How Is the Ferritin Test Performed?
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 will insert a small needle into your blood to obtain a
sample. This sample will then be sent to a laboratory for analysis. You shouldn’t
have to take any special precautions before having the blood test.
Understanding Your Ferritin Blood Test Results
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:
- 24 to 336 nanograms per milliliter in men
- 11 to 307 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 range when determining if your
ferritin levels are normal, high, or low.
Causes of Low Ferritin Levels
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
- excessive menstrual bleeding
- stomach conditions that affect intestinal
- internal bleeding
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
Causes of 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
- liver disease
- adult Still’s disease
- type 2 diabetes
- Hodgkin’s lymphoma
- iron poisoning
- frequent blood transfusions
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 that 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
patients with these and other inflammatory conditions.
According to an article in Gastroenterology
& Hepatology, 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
Side Effects of a Ferritin Blood Test
A ferritin blood test is not 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
- excess bleeding
- feeling faint or light-headed
Always notify your medical provider if you experience
discomfort that seems out of the norm.