At a Glance
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.
The Test Sample
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.
Ask a Laboratory Scientist
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Devkota, B. (Updated 2012 May 21). Ferritin. Medscape Reference [On-line information]. Available online at http://emedicine.medscape.com/article/2085454-overview through http://emedicine.medscape.com. Accessed May 2013.
Gersten, T. (Updated 2012 February 8). Ferritin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003490.htm. Accessed May 2013.
(© 1995–2013). Ferritin, Serum. Mayo Clinic Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/8689 through http://www.mayomedicallaboratories.com. Accessed May 2013.
(Update 2013 March). Hemochromatosis. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/Hemochromatosis.html?client_ID=LTD#tabs=6 through http://www.arupconsult.com. Accessed April 2013.
Hämäläinen, P. et. al. (2012). Erythropoietin, Ferritin, Haptoglobin, Hemoglobin and Transferrin Receptor in Metabolic Syndrome, A Case Control Study. Medscape Reference Cardiovasc Diabetol. 2012;11(116) [On-line information]. Available online at http://www.medscape.com/viewarticle/774074 through http://www.medscape.com. Accessed May 2013.
Lichtin, A. (Revised 2008 June). Iron Deficiency Anemia (Anemia of Chronic Blood Loss; Chlorosis). Merck Manual for Healthcare Professionals [On-line information]. Available online through http://www.merckmanuals.com. Accessed May 2013.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 443-444.
Clarke, W., Editor (© 2011). Contemporary Practice in Clinical Chemistry 2nd Edition: AACC Press, Washington, DC. Pg 536.
McPherson, R. and Pincus, M. (© 2011). Henry's Clinical Diagnosis and Management by Laboratory Methods 22nd Edition: Elsevier Saunders, Philadelphia, PA. Pg 560.
Sources Used in Previous Reviews
Corbett, JV. Laboratory Tests & Diagnostic Procedures with Nursing Diagnoses, 4th ed. Stamford, Conn.: Appleton & Lang, 1996. Pp. 34-35, 41-43.
Frey, Rebecca J. Iron Tests. Chapter in: Gale Encyclopedia of Medicine, Edition One, 1999 Gale Research Group, Pg. 1648.
Witte DL, Crosby WH, Edwards CQ, Fairbanks VG, Mitros FA: Practice guideline development task force of the College of American Pathologists.
Boston University Medical Center: Community Outreach Health Information System. Available online at http://www.bu.edu/cohis/cardvasc/blood/anemia.htm#prevent through http://www.bu.edu.
Lyon, Elaine and Frank, Elizabeth L. Hereditary Hemochromatosis Since Discovery of the HFE Gene. Clinical Chemistry 47:1147-1156 (Jul 2001).
Pagana, K. D. & Pagana, T. J. (© 2007). Mosby's Diagnostic and Laboratory Test Reference 8th Edition: Mosby, Inc., Saint Louis, MO. Pp 434-435.
Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests, 4th Edition: Saunders Elsevier, St. Louis, MO. Pp 392-393.
Gersten, T. (Updated 2009 January 12). Ferritin. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003490.htm. Accessed June 2009.
(Modified 2009 March 13). About Iron. Iron Disorders Institute [On-line information]. Available online at http://www.irondisorders.org/Disorders/about.asp through http://www.irondisorders.org. Accessed June 2009.
(Updated 2007 August 24). Dietary Supplement Fact Sheet: Iron. NIH Office of Dietary Supplements [On-line information]. Available online at http://ods.od.nih.gov/factsheets/iron.asp through http://ods.od.nih.gov. Accessed June 2009.
Rathz, D. et. al. (Updated 2009 February 02). Toxicity, Iron. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/166933-overview through http://emedicine.medscape.com. Accessed June 2009.
Chen, Y. (Updated 2009 April 05). Iron Deficiency Anemia. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000584.htm. Accessed June 2009.
Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson RA and Pincus MR, eds. Philadelphia: 2007, Pg 506.