From the Guidelines
In iron deficiency anemia, ferritin levels typically fall below 45 ng/mL, with severe deficiency often showing levels under 15 ng/mL, as indicated by the most recent guidelines 1.
Diagnosis and Treatment
To diagnose iron deficiency anemia, serum ferritin concentration is a key indicator, with levels less than 45 ng/mL suggesting iron deficiency, especially in patients with anemia 1.
- The sensitivity and specificity of low serum ferritin concentration for iron deficiency vary, but a level of less than or equal to 15 ug/L is often used to confirm iron deficiency 1.
- Treatment primarily involves oral iron supplementation, usually with ferrous sulfate 325 mg taken 1-3 times daily between meals with vitamin C to enhance absorption.
- Alternative options include ferrous gluconate or ferrous fumarate for patients who experience gastrointestinal side effects from ferrous sulfate.
- For those who cannot tolerate oral iron or have malabsorption issues, intravenous iron formulations like iron sucrose or ferric carboxymaltose may be necessary 1.
Monitoring and Dietary Changes
- Iron therapy effectiveness can be monitored through rising hemoglobin levels (typically within 2-4 weeks) and normalizing ferritin levels, which may take several months of consistent treatment.
- Dietary changes to include iron-rich foods such as red meat, spinach, and legumes can complement medical treatment.
- The underlying cause of iron deficiency should also be identified and addressed, whether it's blood loss, poor dietary intake, or malabsorption.
Special Considerations
- In patients with chronic inflammation or liver disease, ferritin levels may be elevated, and other markers of inflammation or iron status should be considered 1.
- Bidirectional endoscopy may be recommended for asymptomatic postmenopausal women and men with iron deficiency anemia, as well as for asymptomatic premenopausal women, to rule out gastrointestinal causes of iron deficiency 1.
From the Research
Typical Ferritin Levels in Iron Deficiency Anemia
- Ferritin levels are typically low in individuals with iron deficiency anemia, with a common cutoff value of <30 ng/mL in individuals without inflammatory conditions 2.
- However, in elderly subjects, iron deficiency anemia may develop with higher levels of serum ferritin, and a cutoff level of 100ng/mL may be more appropriate 3.
- Serum ferritin is an acute phase protein and may increase in response to inflammatory processes, making it a less reliable marker of iron stores in individuals with chronic medical conditions 3.
Treatment of Iron Deficiency Anemia
- Oral iron supplementation is typically the first-line therapy for iron deficiency anemia, with ferrous sulfate 325 mg/d or on alternate days being a common regimen 2.
- Intravenous iron is indicated for patients with oral iron intolerance, poor absorption, chronic inflammatory conditions, ongoing blood loss, and during the second and third trimesters of pregnancy 2.
- Low-dose iron supplementation (<5 mg/kg/day) may be sufficient to increase iron stores and improve hemoglobin levels in individuals with iron deficiency anemia, particularly in children and adolescents 4.
- The optimal duration of iron supplementation varies, but treatment for less than 3 months or more than 6 months may be more effective than treatment lasting 3-6 months 4.
Diagnosis of Iron Deficiency Anemia
- Diagnosis of iron deficiency anemia is typically made by measuring serum ferritin and/or transferrin saturation, in addition to hemoglobin and hematocrit levels 2, 5.
- A complete blood count (CBC) alone may not be sufficient to diagnose iron deficiency anemia, and additional tests such as serum iron and ferritin should be performed to confirm the diagnosis 5.