Normal Adult Female Ferritin Levels
The normal ferritin reference range for adult women is 20-200 μg/L, though values below 30 μg/L generally indicate depleted iron stores that warrant clinical attention. 1
Standard Reference Ranges
The most recent international guidelines establish clear reference intervals:
- Women: 20-200 μg/L (or 11-307 μg/L in some laboratory methods) 1
- The lower limit of normal typically falls between 15-30 μg/L across most laboratories 1
- The CDC reports an average serum ferritin of 43 μg/L for adult women 2
Clinical Interpretation Thresholds
Understanding ferritin values requires recognizing specific diagnostic cutoffs rather than relying solely on laboratory reference ranges:
Iron Deficiency Diagnosis
- <15 μg/L: Highly specific for iron deficiency (99% specificity), indicating absent iron stores 1, 2
- <30 μg/L: Generally indicates low body iron stores and warrants intervention even before anemia develops 1, 2
- <45 μg/L: May warrant gastrointestinal investigation, especially with chronic inflammatory processes (92% specificity) 1
Normal to Elevated Values
- >150 μg/L: Unlikely to represent absolute iron deficiency, even with concurrent inflammation 1
- Values above the upper limit of normal require evaluation for iron overload, inflammation, or other pathology 1
Critical Clinical Caveats
Ferritin is an acute-phase reactant, meaning infections, inflammation, liver disease, or tissue damage can falsely elevate levels independent of actual iron stores 1, 2. This elevation can mask true iron deficiency.
Adjusting for Inflammation
- In the presence of inflammation, iron deficiency may exist with ferritin levels up to 50-100 μg/L 2
- Apparently normal ferritin levels may occur with iron deficiency when inflammatory processes are present 1
- Always interpret ferritin alongside transferrin saturation, inflammatory markers (CRP/ESR), and clinical context 2
Menstruating vs. Non-Menstruating Women
The guidelines distinguish between these populations:
- Premenopausal/menstruating women: Lower ferritin values are more common due to menstrual blood loss 1
- Postmenopausal women: Should be evaluated with the same threshold as men when ferritin is abnormal 1
- Non-anaemic iron deficiency is particularly common in young women with menorrhagia, where over half may have reduced iron stores 1
Practical Algorithm for Interpretation
When evaluating a ferritin result in an adult female:
If <15 μg/L: Absolute iron deficiency confirmed; initiate iron supplementation and investigate source of iron loss 1, 2
If 15-30 μg/L: Iron deficiency with low stores likely; consider iron supplementation 1, 2
If 30-100 μg/L with elevated CRP/ESR: Mixed picture of iron deficiency and inflammation; address underlying inflammatory condition while considering iron supplementation 2
If >100 μg/L with elevated CRP/ESR: Anemia of chronic disease (inflammatory iron block) more likely than true iron deficiency; treat underlying inflammatory condition 2
If >200 μg/L: Above normal range; evaluate for iron overload, chronic inflammation, liver disease, or malignancy 1
Important Methodological Considerations
Laboratory methods vary significantly, and no generic reference ranges are universally agreed upon 1. Each laboratory should indicate its own reference ranges based on the specific immunological method used for ferritin determination 1.
Recent systematic reviews reveal that many ferritin reference intervals are at high risk of bias, as they often fail to exclude individuals at risk for iron deficiency from the "normal" population sample 3. This contributes to structural underdiagnosis of iron deficiency when relying solely on laboratory-reported lower limits of normal 3.