Management of Marginally Low Hemoglobin

Diagnostic Approach for Marginally Low Hemoglobin

A complete iron panel should be ordered including serum ferritin, transferrin saturation, and C-reactive protein to confirm iron deficiency before starting supplementation 1
Serum ferritin is the single most useful marker of iron deficiency anemia (IDA), with levels <30 μg/L generally indicating low body iron stores 1
Transferrin saturation <20% suggests iron deficiency, even when ferritin appears normal 2, 3
C-reactive protein should be measured to exclude false-normal ferritin results due to inflammation 3, 4
A good response to iron therapy (Hb rise ≥10 g/L within 2 weeks) is highly suggestive of iron deficiency, even with equivocal iron studies 1

All patients with marginally low hemoglobin should have iron studies performed 1, 2
Iron studies help identify the underlying cause of anemia, which may require specific treatment 5

Intravenous iron should be considered for patients with clinically active inflammatory bowel disease 3, 6
Intravenous iron should be considered for patients with previous intolerance to oral iron 6
Intravenous iron should be considered for patients with hemoglobin below 10 g/dL 6
Intravenous iron should be considered for patients with need for erythropoiesis-stimulating agents 6

Starting iron without confirming deficiency can mask underlying conditions requiring treatment 1
Failing to recognize that normal ferritin does not exclude iron deficiency in inflammatory states 4
Overlooking functional iron deficiency (normal ferritin, low transferrin saturation) which may not respond to oral iron 4