How to manage iron deficiency with low ferritin and iron saturation?

Management of Iron Deficiency with Low Ferritin and Iron Saturation

The patient has iron deficiency without anemia and should be treated with oral iron supplementation of ferrous sulfate 324 mg (65 mg elemental iron) daily for three months to replenish iron stores. 1

Diagnosis Assessment

• The patient's laboratory values confirm iron deficiency with:

  • Low ferritin (11 ng/mL; reference range 15-150 ng/mL) 1
  • Low iron saturation (8%; reference range 15-55%) 1
  • Normal hemoglobin (14.7 g/dL; reference range 11.1-15.9 g/dL) 1

• This represents iron deficiency without anemia, as ferritin <30 ng/mL is diagnostic of depleted iron stores even with normal hemoglobin 1, 2

• The combination of low ferritin and low transferrin saturation is highly specific (98%) for iron deficiency 1, 3

Treatment Approach

First-Line Therapy

• Oral iron supplementation is the first-line treatment for non-anemic iron deficiency 1, 2

  • Ferrous sulfate 324 mg (providing 65 mg of elemental iron) daily is recommended 4, 5
  • Treatment should continue for three months after correction of deficiency to fully replenish iron stores 1

• Alternative oral preparations if ferrous sulfate is not tolerated:

  • Ferrous gluconate or ferrous fumarate are equally effective alternatives 1
  • Liquid preparations may be better tolerated in some patients 1
  • Adding ascorbic acid (vitamin C) can enhance iron absorption if response is poor 1

Monitoring Response

• Expect improvement in iron parameters within 4 weeks of starting therapy 1
• Follow-up testing should include:
  • Ferritin and transferrin saturation after 8-10 weeks of therapy 1
  • Once normalized, monitor iron parameters every three months for one year, then annually 1

Special Considerations

• If oral iron is not tolerated or ineffective, consider:
  • Trying alternate-day dosing which may improve absorption and reduce side effects 1
  • Evaluating for causes of poor absorption such as celiac disease, atrophic gastritis, or inflammatory conditions 2
  • Switching to intravenous iron if oral therapy fails after adequate trial 1

Evaluation for Underlying Causes

• Common causes of iron deficiency that should be investigated:

  • Blood loss (menstrual, gastrointestinal) 2, 5
  • Malabsorption (celiac disease, inflammatory bowel disease, gastric surgery) 2
  • Inadequate dietary intake 2
  • Increased requirements (pregnancy) 2

• In men and post-menopausal women, gastrointestinal evaluation is warranted to rule out occult bleeding 1, 5

Pitfalls and Caveats

• Ferritin is an acute phase reactant and may be falsely elevated in inflammatory conditions, masking iron deficiency 1

  • In inflammatory states, ferritin up to 100 ng/mL may still represent iron deficiency 1, 6

• Common side effects of oral iron include:

  • Gastrointestinal symptoms (constipation, diarrhea, nausea) 1
  • Taking with food may reduce side effects but also reduces absorption 5

• Intravenous iron should be reserved for:

  • Intolerance to at least two oral preparations 1
  • Documented malabsorption 2
  • Active inflammatory bowel disease 1
  • Need for rapid repletion 1, 2