Iron Deficiency Anemia Diagnosis and Treatment

Diagnostic Criteria

Serum ferritin <15 μg/L indicates absent iron stores, while <30 μg/L indicates low body iron stores 1, 2
A ferritin cut-off of 45 μg/L provides optimal sensitivity and specificity for diagnosing iron deficiency in clinical practice 1, 2
Transferrin saturation (TSAT) is low and more sensitive than hemoglobin alone for detecting iron deficiency 1, 2
Low MCV combined with RDW >14.0% strongly suggests iron deficiency anemia, while low MCV with RDW ≤14.0% suggests thalassemia minor 1
Serum iron is low and total iron binding capacity (TIBC) is elevated 2

The first-line treatment for microcytic hypochromic anemia due to iron deficiency is oral ferrous sulfate 324 mg (65 mg elemental iron) taken one to three times daily for at least three months after hemoglobin normalizes to replenish iron stores 1, 2
Alternative oral formulations include ferrous gluconate or ferrous fumarate if ferrous sulfate causes intolerable gastrointestinal side effects 1, 2
Adding ascorbic acid (vitamin C) enhances iron absorption 1, 2
A good response is defined as hemoglobin rise ≥10 g/L (≥1 g/dL) within 2 weeks, which confirms iron deficiency 1, 2
Expected hemoglobin increase should be at least 2 g/dL within 4 weeks of starting treatment 1

Hypotransferrinemia (TF Gene Defects) iron profile shows low transferrin, low TSAT, but HIGH ferritin 4, 5
SLC11A2 (DMT1) Defects iron profile shows microcytic anemia with HIGH TSAT and variable ferritin 4, 5
IRIDA (TMPRSS6 Mutations) iron profile shows very low TSAT, low-to-normal ferritin, and resistance to oral iron 3
Treatment for IRIDA requires intravenous iron (iron sucrose or iron gluconate) as oral iron is typically ineffective 3, 1

Check hemoglobin, MCV, and iron studies at 2 weeks, 4 weeks, 3 months, and every 3 months for the first year, then annually thereafter 1, 2
Provide additional oral iron if hemoglobin or MCV falls below normal during follow-up 1, 2