What is the treatment for a patient with low ferritin (iron storage) and transferrin saturation levels, indicating iron deficiency anemia?

Treatment of Iron Deficiency with Ferritin 9 and Transferrin Saturation 11%

Oral iron supplementation is the first-line treatment for this patient with confirmed absolute iron deficiency, using ferrous sulfate 325 mg daily (65 mg elemental iron) for at least 3 months to replenish depleted iron stores. 1, 2

Diagnostic Confirmation

Your laboratory values definitively confirm absolute iron deficiency:

• Ferritin <15 μg/L indicates depleted iron stores with 98% specificity for iron deficiency 3, 1
• Transferrin saturation <16% confirms iron-deficient erythropoiesis 3
• This combination is diagnostic even in the absence of anemia 1, 2

Treatment Algorithm

First-Line: Oral Iron Therapy

Start ferrous sulfate 325 mg once daily (containing 65 mg elemental iron) 1, 2:

• Continue for 3 months minimum to fully replenish iron stores, even after hemoglobin normalizes 1
• Alternative dosing: every other day may improve absorption and reduce side effects by avoiding hepcidin elevation 3
• Take with vitamin C (ascorbic acid) to enhance absorption if response is suboptimal 1
• Avoid taking with food, antacids, or proton pump inhibitors which impair absorption, though taking with food may be necessary if gastrointestinal side effects occur 3

When to Use Intravenous Iron Instead

Intravenous iron should be first-line if the patient has 3, 1, 2:

• Intolerance to at least two different oral iron preparations 1
• Malabsorption conditions (celiac disease, inflammatory bowel disease, post-bariatric surgery) 3, 2
• Chronic inflammatory conditions (chronic kidney disease, heart failure, active IBD, cancer) 3
• Ongoing blood loss that cannot be controlled 2
• Pregnancy in second or third trimester 2
• Hemoglobin <100 g/L requiring rapid correction 3

Monitoring Response

Recheck complete blood count, ferritin, and transferrin saturation after 8-10 weeks of treatment 1, 4:

• Expect improvement in iron parameters within 4 weeks 1
• Target ferritin >30 μg/L and transferrin saturation >20% 3, 1
• Once normalized, monitor every 3 months for 1 year, then annually 1

Evaluation for Underlying Causes

Investigate the source of iron deficiency 2, 5:

• In men and postmenopausal women: gastrointestinal evaluation is mandatory to exclude occult bleeding or malignancy 3, 1
• In premenopausal women: assess for heavy menstrual bleeding (most common cause) 2
• Consider dietary assessment for inadequate intake or vegetarian/vegan diet 4
• Screen for malabsorption (celiac disease, atrophic gastritis, H. pylori infection) 5
• Review medications (NSAIDs, anticoagulants, proton pump inhibitors) 3, 2

Critical Pitfalls to Avoid

Ferritin is an acute-phase reactant and can be falsely elevated in inflammatory conditions, masking true iron deficiency 3:

• In the presence of inflammation, ferritin up to 100 μg/L may still represent iron deficiency 3
• Check C-reactive protein to exclude inflammation if ferritin is between 30-100 μg/L 3, 4

Common oral iron side effects include nausea, constipation, and abdominal discomfort 3:

• These occur in up to 40% of patients and are the main cause of non-compliance 4
• Lower doses (28-50 mg elemental iron) or alternate-day dosing may improve tolerance 3, 4

Do not continue long-term iron supplementation once stores are replenished 4:

• Iron supplementation with normal or high ferritin is potentially harmful and should be avoided 4
• For patients with recurrent deficiency, use intermittent oral supplementation rather than continuous therapy 4

Transferrin saturation has significant diurnal and day-to-day variation 3:

• Values are highest in the morning and after meals 3
• Repeat testing if results are inconsistent with clinical picture 3