Management of Severe Iron‑Deficiency Anemia in Adult Women

Immediate Management

Initiate intravenous iron as first‑line therapy in patients with severe iron‑deficiency anemia (e.g., hemoglobin ≈6 g/dL) rather than oral iron, because IV iron provides faster repletion in this setting. 3

Expect a rise in hemoglobin of at least 10 g/L within 2 weeks after iron therapy; such an increase confirms absolute iron deficiency even when baseline iron studies are equivocal. [1][2]

Serum ferritin < 15 µg/L is 99 % specific for iron deficiency, while a threshold < 45 µg/L offers the best balance of sensitivity and specificity. [1][4]
When inflammation may elevate ferritin, assess transferrin saturation (or other iron markers) to avoid false‑negative results. [1][4]

Obtain a detailed menstrual history to identify menometrorrhagia, the leading cause of severe iron deficiency in premenopausal women. 1

Perform urinalysis or urine microscopy to rule out occult urinary blood loss. [1][2]
Screen for celiac disease with tissue transglutaminase antibodies; celiac disease accounts for 3–5 % of iron‑deficiency anemia cases and impairs iron absorption. [1][2]5
Conduct a dietary assessment focusing on iron intake and intake of absorption inhibitors (e.g., phytates, calcium). [3][1]

Bidirectional endoscopy (upper endoscopy + colonoscopy) is the first‑line investigation for women without an obvious menstrual source, especially post‑menopausal patients; approximately one‑third of such cases reveal underlying GI pathology, including malignancy. [1][2]5
If colonoscopy cannot be performed, CT colonography is an acceptable alternative. [1][2]

Order hemoglobin electrophoresis when iron studies are normal or when the mean corpuscular volume is disproportionately low relative to anemia severity, particularly in individuals of Mediterranean, African, or Asian ancestry. 4

Do not postpone gastrointestinal evaluation while initiating iron therapy; the severity of anemia and the risk of serious pathology (e.g., malignancy) mandate urgent work‑up. [1][2]5
Do not attribute severe anemia solely to menstrual blood loss without first excluding concurrent GI disease, especially when menstrual loss is not clearly excessive. 1
Do not rely exclusively on ferritin in the presence of inflammation; incorporate transferrin saturation or alternative iron markers to improve diagnostic accuracy. [1][4]
Do not overlook thalassemia trait; a very low MCV (< 60 fL) with only mild anemia suggests a hemoglobinopathy rather than pure iron deficiency. 4

Re‑measure hemoglobin after 2 weeks; a rise of ≥10 g/L supports iron deficiency as the underlying cause. [1][2]
If the hemoglobin response is inadequate or anemia recurs after initial correction, proceed to capsule endoscopy for small‑bowel evaluation (preferred over CT/MR enterography for detecting mucosal lesions). [1][2]
Consider long‑term iron supplementation when the underlying cause is irreversible or remains unidentified after a complete work‑up. [1][2]