Ferritin is the storage form of iron in the body, storing up to 80% of the total amount of iron. Since iron is stored in the body as ferritin, a serum ferritin test is the most reliable screening test for iron status. Iron deficiency causes lots of symptoms, including fatigue, shortness of breath, rapid heart rate, dizziness, depression, difficulty processing information (brain fog), decreased memory (forgetfulness) and feeling cold.
- Serum ferritin
Methodology: Immunoassay (IA)
Water: Drink plenty of water to stay well hydrated.
Medications: Take all medications as prescribed.
Dietary supplements: Do not take dietary supplements before taking this test.
2 business days
Result turnaround times are estimates and not guaranteed. Due to factors outside of our control, such as weather, holidays, confirmation/repeat testing or equipment maintenance, our lab may require additional time to complete tests.
The largest concentrations of ferritin are in the liver, spleen, bone marrow and skeletal muscles. However, some ferritin circulates in the blood, which is why it can be detected on a blood test.
For labs reporting this value, 50 ng/mL is still within the “normal” range; however, experts agree that that iron deficiency is likely when the ferritin level falls below 50 ng/ml. A large study of nearly 200 women ages 18-53 years confirms that iron supplementation should begin long before a person’s serum ferritin drops below 12 ng/ml. Women were admitted into the study if they had normal CBC test results but levels of ferritin less than 50 and if they also complained of fatigue. Women in the study who took an iron dietary supplement for 12 weeks experienced a nearly 48% improvement in their energy.
Another study reported benefit from taking iron when ferritin was less than 50 ng/ml in people with restless leg syndrome (RLS).
When serum ferritin is low it indicates low iron status. However, when ferritin is high it may indicate too much iron or the presence of inflammation. A serum ferritin greater than 400 ng/mL, is consistent with iron overload, a disorder called hemochromatosis.
The Most Important Lab Test Women Aren’t Getting, by Dr. Neustadt
Tired? Breathless? RLS? Iron Deficiency Might be the Cause, by Dr. Neustadt
Anemia Special Report, by Dr. Neustadt
Mackie S, Winkelman JW. Normal ferritin in a patient with iron deficiency and RLS. J Clin Sleep Med. 2013;9(5):511-513.
Recommendations to Prevent and Control Iron Deficiency in the United States. MMWR 1998;47(No. RR-3). Atlanta, GA: Centers for Disease Control and Prevention;1998.
Vaucher P, Druais PL, Waldvogel S, Favrat B. Effect of iron supplementation on fatigue in nonanemic menstruating women with low ferritin: a randomized controlled trial. CMAJ. 2012;184(11):1247-1254.
Wang W, Knovich MA, Coffman LG, Torti FM, Torti SV. Serum ferritin: Past, present and future. Biochim Biophys Acta. 2010;1800(8):760-769.