Also known as:Serum Ferritin
Formal name:Ferritin, serum
Related tests:Complete Blood Count, Hemoglobin, Hematocrit, Serum Iron, TIBC, UIBC and Transferrin, Iron Tests, Zinc Protoporphyrin, Soluble Transferrin Receptor
Why Get Tested?
To determine your body's total iron storage capacity
When to Get Tested?
When your doctor suspects that you may have too little or too much iron in your system
A blood sample drawn from a vein in your arm
Test Preparation Needed?
You may be instructed to fast for 12 hours before the test; in this case, only water is permitted.
How is it used?
The ferritin test is ordered to assess a person's iron stores in the body. The test is sometimes ordered along with an iron test and a TIBC to detect the presence and severity of iron deficiency or iron overload.
When is it ordered?
The ferritin test may be ordered, along with other iron tests, when a routine CBC shows that a person's hemoglobin and hematocrit are low and their red blood cells are smaller and paler than normal (microcytic and hypochromic), suggesting iron deficiency anemia even though other clinical symptoms may not have developed yet.
In the early stage of iron deficiency, no physical effects are usually seen. If a person is otherwise healthy, symptoms seldom appear before the hemoglobin in the blood drops below a certain level (10 g per deciliter). However, as the iron-deficiency progresses, symptoms eventually begin to develop and a doctor may order ferritin as well as other iron-related tests. The most common symptoms of iron deficiency anemia include:
- chronic fatigue/tiredness
- Pale skin (pallor)
As iron stores continue to be depleted, there may be shortness of breath, ringing in the ears (tinnitus), drowsiness, and irritability. If the anemia progresses in severity, chest pain, headaches, leg pains, shock, and even heart failure may occur. Children may develop learning (cognitive) disabilities. Besides the general symptoms of anemia, there are certain symptoms that are characteristic of iron deficiency. These include pica (cravings for specific substances, such as licorice, chalk, dirt, or clay), a burning sensation in the tongue or a smooth tongue, sores at the corners of the mouth, and spoon-shaped finger- and toe-nails.
A ferritin level may also be ordered when iron overload is suspected. Symptoms of iron overload will vary from person to person and tend to worsen over time. They are due to iron accumulation in the blood and tissues. Symptoms may include:
- Joint pain
- Fatigue, weakness
- Weight loss
- Lack of energy
- Abdominal pain
- Loss of sex drive
- Loss of body hair
- Heart problems such as congestive heart failure (CHF)
What does the test result mean?
Ferritin levels are often evaluated in conjunction with other iron tests. A summary of the changes in iron tests seen in various diseases of iron status is shown in the table below.
Ferritin levels are low in people who are iron deficient and are elevated in those with hemochromatosis or who have had multiple blood transfusions.
Ferritin is an acute phase reactant and can be increased in people with inflammation, liver disease, chronic infection, autoimmune disorders, and some types of cancer. Ferritin is not typically used to detect or monitor these conditions.
Is there anything else I should know?
Normally, most ferritin is found inside of cells with only a small amount in the blood. When there is damage to organs that contain ferritin, such as the liver, spleen, and bone marrow, ferritin levels can become elevated even though the total amount of iron in the body is normal.
What is being tested?
Ferritin is an iron-containing protein and is the primary form of iron stored inside of cells. The small quantity of ferritin that is released into the blood is a reflection of the amount of total iron stored in the body. This test measures the amount of ferritin in the blood.
In healthy people, about 70% of the iron absorbed by the body is incorporated into the hemoglobin of red blood cells. Most of the remaining 30% is stored as ferritin or as hemosiderin, a complex of iron, proteins, and other materials. Ferritin and hemosiderin are present primarily in the liver but also in the bone marrow, spleen, and skeletal muscles.
When available iron is insufficient to meet the body's needs, iron stores are depleted and ferritin levels decrease. This may occur because of insufficient iron intake, inadequate absorption, or increased need for iron such as during pregnancy or due to a condition that causes chronic blood loss. Significant depletion of iron stores may occur before any signs of iron deficiency develop.
Iron storage and ferritin levels increase when more iron is absorbed than the body needs. Chronic absorption of excess iron will lead to the progressive buildup of iron compounds in organs and may eventually cause their dysfunction and failure. This happens in hemochromatosis, a genetic disease in which the body absorbs too much iron, even on a normal diet.
How is the sample collected for testing?
A blood sample is drawn by needle from a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
A 12-hour fast may be required. In this case, only water is permitted. Morning specimens are preferred.
- My iron level is normal, but my ferritin level is low. Why is that?
The development of iron deficiency anemia is a gradual process. If your body is not taking in enough iron, your body first uses the iron that is stored in tissues (i.e., ferritin) and blood levels of ferritin will begin to decrease. If not corrected, the stored iron begins to be depleted as it is used in the production of red blood cells. In the early stages of iron-deficiency, blood levels of iron can be normal while stored iron, and therefore ferritin levels, will begin to decrease.
- I know eating foods high in iron or taking iron supplements will increase my iron level, but will it also increase my ferritin level?
Yes. Taking in more iron will increase the level of iron in your body. If the level of iron in your body increases and is more than your body requires, then your body will begin to store more iron in the form of ferritin.
- What other conditions may alter ferritin levels?
Increased levels may be seen in alcohol abuse, acute hepatitis, and infections.
- Who should take iron supplements?
The people who typically need iron supplements are pregnant women and those with documented iron deficiency. Young women who become anemic due to poor dietary intake and have chronic and/or excessive loss of blood during their menstrual cycle may require iron supplements. People should not take iron supplements before talking to their doctor as excess iron can cause chronic iron overload. An overdose of iron pills can be toxic, especially to children.
- Is there any way to cure iron overload?
If it is due to a temporary condition or ingestion of iron supplements, then it will likely resolve on its own once the condition or supplement ingestion is resolved. If it is due to hemochromatosis or to a chronic disease, then it cannot be cured; careful management by your physician is required. In severe cases, periodic removal of a prescribed amount of blood, also known as therapeutic phlebotomy, may be necessary.
© 2017 American Association for Clinical Chemistry, republished from Lab Tests Online.*
Descriptions of clinical laboratory tests were originally prepared for use on Lab Tests Online, an award-winning patient education website on clinical laboratory testing. Lab Tests Online is produced by the American Association for Clinical Chemistry (AACC), a global scientific and medical professional organization dedicated to clinical laboratory science and its application to healthcare. The Lab Tests Online website is developed in collaboration with other laboratory professional societies and is funded in part through corporate sponsorships.