From the Guidelines
Iron deficiency should be diagnosed if ferritin levels are less than 45 ng/mL, as recommended by the American Gastroenterological Association (AGA) 1. When evaluating iron deficiency anemia, it is essential to consider the underlying causes, particularly in patients with gastrointestinal symptoms.
- The AGA recommends using a cut-off of 45 ng/mL when using ferritin to diagnose iron deficiency, which provides a respectable specificity of 0.92 1.
- In patients with anemia, additional laboratory tests may be needed to confirm iron deficiency, especially if there is underlying inflammation or chronic kidney disease 1.
- The British Society of Gastroenterology guidelines also support the use of serum ferritin as a specific test for iron deficiency, with a cut-off of 45 μg/L providing a good trade-off between sensitivity and specificity 1.
- It is crucial to note that serum ferritin is an acute phase protein, and apparently normal levels may occur with iron deficiency in the context of an inflammatory disease process 1.
- Therefore, a ferritin level of less than 45 ng/mL is a reliable indicator of iron deficiency, and patients with such levels should be considered for further evaluation and treatment 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Iron Deficiency and Anemia
- Iron deficiency and iron-deficiency anemia are common conditions that affect approximately 2 billion people worldwide, with 14% of adults in the US having absolute iron deficiency and 10% having iron-deficiency anemia 2.
- The most common causes of iron deficiency are bleeding, impaired iron absorption, inadequate dietary iron intake, and pregnancy 2.
- Symptoms of iron deficiency and iron-deficiency anemia may include fatigue, irritability, depression, difficulty concentrating, restless legs syndrome, pica, dyspnea, lightheadedness, exercise intolerance, and worsening heart failure 2.
Diagnosis and Treatment
- Iron deficiency is diagnosed by low serum ferritin or transferrin saturation, and causes of iron deficiency should be identified and treated 2.
- Oral iron is typically first-line therapy, with ferrous sulfate 325 mg/d or on alternate days being a common treatment 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, 3, 4.
- Sucrosomial iron is a new oral iron formulation that has been shown to be effective in correcting iron deficiency anemia, with higher iron intestinal absorption and excellent gastrointestinal tolerance compared to oral iron salts 5.
Iron Supplementation
- Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women 6.
- Alternate day dosing of oral iron supplements may be preferable because it sharply increases fractional iron absorption, and twice the daily target dose should be given on alternate days to provide the same total amount of iron 6.
- Intravenous iron sucrose and oral iron ferrous sulfate are both effective in correcting peripartum anemia, although intravenous iron restores stores faster than oral iron 4.