From the Guidelines
Low serum ferritin levels are primarily associated with iron deficiency, which can result from chronic blood loss, inadequate dietary iron intake, malabsorption disorders, increased iron requirements, and certain medications. The conditions associated with low serum ferritin levels include:
- Chronic blood loss (such as from heavy menstrual periods, gastrointestinal bleeding, or frequent blood donation)
- Inadequate dietary iron intake
- Malabsorption disorders (like celiac disease or inflammatory bowel disease)
- Increased iron requirements (during pregnancy, infancy, or adolescence)
- After gastric bypass surgery
- Certain medications that interfere with iron absorption, including proton pump inhibitors, antacids, and some antibiotics According to the most recent study 1, iron deficiency anemia may be diagnosed with a serum ferritin level <30 mg/L in the absence of inflammation, and a serum ferritin level up to 100 mg/L may still be consistent with iron deficiency in the presence of inflammation. Treatment generally involves addressing the underlying cause and may include iron supplementation, typically with ferrous sulfate or ferrous gluconate, taken on an empty stomach with vitamin C to enhance absorption. For severe deficiency, intravenous iron may be necessary, as recommended by the European Crohn's and Colitis Organization guidelines 1. Low ferritin reflects depleted iron stores before anemia develops, making it an early and sensitive marker of iron deficiency.
From the Research
Conditions Associated with Low Serum Ferritin Levels
Low serum ferritin levels are indicative of iron deficiency, which can be caused by various conditions, including:
- Increased demand for iron
- Inadequate iron intake
- Decreased iron absorption (malabsorption)
- Increased blood loss
- Defective plasma iron transport 2
- Iron deficiency anemia, which can result in neurodevelopmental and cognitive deficits, especially in children 2
Thresholds for Iron Deficiency
Studies have identified different thresholds for iron deficiency based on serum ferritin levels, including:
- 10 µg/L, below which iron deficiency anemia starts to occur 3
- 19.9 µg/L for children and 25.2 µg/L for non-pregnant women, based on physiologically based serum ferritin thresholds 4
- 50 ng/mL, below which the soluble transferrin receptor to hepcidin ratio begins to correlate significantly with ferritin levels 5
- 100 ng/mL, which can differentiate patients with and without iron deficiency anemia in elderly subjects with a sensitivity of 60% and specificity of 59% 6
Population-Specific Considerations
Different populations may have varying thresholds for iron deficiency, including: