What is the management for an adult patient with low ferritin (iron storage protein) levels and normal iron levels, presenting with symptoms of iron deficiency such as fatigue, weakness, or pale skin?

Management of Low Ferritin with Normal Hemoglobin/Hematocrit

Start oral iron supplementation immediately—low ferritin (<15-30 μg/L) indicates depleted iron stores requiring treatment even without anemia, as iron deficiency causes symptoms and impairs quality of life independent of hemoglobin levels. 1, 2, 3

Diagnosis Confirmation

Your patient has absolute iron deficiency despite normal hemoglobin:

• Ferritin <15 μg/L is diagnostic of depleted iron stores, even with normal hemoglobin 1, 2
• Ferritin <30 μg/L generally indicates low body iron stores in healthy adults without inflammation 1, 4
• Check C-reactive protein to exclude false-normal ferritin from concurrent inflammation 4, 5
• Consider transferrin saturation if inflammation is suspected (iron deficiency if <20%) 1, 3, 5

Why Treatment is Necessary Without Anemia

Iron deficiency causes significant symptoms before anemia develops:

• Fatigue, reduced physical performance, cognitive impairment, headache, sleeping disorders, and restless legs syndrome occur with depleted stores alone 1, 3
• Impaired nail growth, skin defects, and mucosal regeneration result from iron deficiency 1, 2
• All patients with confirmed iron deficiency should receive supplementation to replenish body stores, regardless of hemoglobin level 1, 2

First-Line Treatment Protocol

Oral iron is the initial treatment:

• Ferrous sulfate 200 mg once daily (or equivalent ferrous gluconate/fumarate) 1, 2
• If gastrointestinal side effects occur, switch to alternate-day dosing (one tablet every other day), which improves absorption and reduces side effects 1, 2
• Adding ascorbic acid 250-500 mg with iron enhances absorption 1, 2
• Avoid preparations exceeding 100 mg elemental iron daily—higher doses increase side effects without improving absorption 2

Treatment Duration

Continue iron for 3 months after ferritin normalizes to fully replenish stores:

• Standard treatment duration is 3 months post-correction to ensure adequate store repletion 1, 2
• Monitor response with hemoglobin and ferritin at 8-10 weeks after starting treatment 2, 4
• A hemoglobin rise ≥10 g/L within 2 weeks confirms iron deficiency even if initial studies were equivocal 1

Long-Term Monitoring

Follow-up schedule after normalization:

• Every 3 months for the first year, then annually 1, 2
• Restart iron if ferritin drops below normal or symptoms recur 1, 2
• Patients with recurrent deficiency benefit from intermittent oral supplementation to maintain stores 4

When to Use Intravenous Iron

Reserve parenteral iron for specific situations only:

• Intolerance to at least two different oral iron preparations 1, 2
• Malabsorption conditions (celiac disease, post-bariatric surgery, inflammatory bowel disease) 2, 3
• Chronic inflammatory conditions where oral iron is ineffective (chronic kidney disease, heart failure) 1, 3, 5
• Do not delay oral iron while investigating the underlying cause—start treatment immediately 1, 2

Investigation for Underlying Cause

While starting iron supplementation, evaluate for causes:

• Screen for celiac disease (tissue transglutaminase antibody)—found in 3-5% of iron deficiency cases 1
• Urinalysis to exclude urinary blood loss 1
• In premenopausal women, menstrual loss is the most common cause; GI investigation reserved for age ≥50 years, GI symptoms, or family history of colorectal cancer 1
• In men and postmenopausal women, bidirectional endoscopy (gastroscopy and colonoscopy) is first-line investigation 1

Critical Pitfalls to Avoid

• Never delay iron supplementation while awaiting investigations—treat immediately 1, 2
• Stop iron once stores are replenished—excessive iron with normal/high ferritin is potentially harmful 2, 4
• Do not continue supplementation indefinitely without monitoring ferritin levels 2
• In inflammatory conditions (CKD, heart failure, IBD), use higher ferritin thresholds (<100 μg/L) for diagnosis, as standard thresholds miss iron deficiency 1, 5