What is the diagnosis and treatment for iron deficiency anemia with low Ferritin and high Total Iron-Binding Capacity (TIBC)?

Iron Deficiency Anemia: Diagnosis and Treatment

Your laboratory values (ferritin 11 ng/mL and TIBC 507 mg/dL) confirm iron deficiency anemia, and you should begin oral iron supplementation immediately while investigating the underlying cause of blood loss. 1

Diagnostic Confirmation

Your results definitively establish iron deficiency:

• Ferritin of 11 ng/mL is well below the diagnostic threshold of <30 ng/mL for iron deficiency in patients without inflammation 1
• Elevated TIBC of 507 mg/dL (normal range typically 240-450 mg/dL) indicates your body is attempting to compensate for low iron stores by producing more transferrin to capture whatever iron is available 1, 2
• The AGA recommends using a ferritin cut-off of <45 ng/mL for diagnosing iron deficiency in anemic patients, making your diagnosis unequivocal 1

Identifying the Underlying Cause

The most critical next step is determining why you are iron deficient, as treatment of the underlying cause is essential 3, 4:

For Postmenopausal Women and Men:

• Bidirectional endoscopy (both upper endoscopy and colonoscopy) is strongly recommended to evaluate for gastrointestinal bleeding or malignancy 1
• Approximately 9% of patients over 65 years with iron deficiency anemia have gastrointestinal cancer 5

For Premenopausal Women:

• Heavy menstrual bleeding is the most common cause (38% have iron deficiency without anemia, 13% have iron deficiency anemia) 3
• Bidirectional endoscopy is conditionally recommended even in premenopausal women, though you may reasonably defer if menstrual losses are clearly the cause 1

Additional Testing to Consider:

• Celiac disease serologic testing (tissue transglutaminase antibodies) before proceeding to endoscopy, as celiac disease is a well-recognized cause even in asymptomatic patients 1
• Non-invasive H. pylori testing (stool antigen or urea breath test), as infection can contribute to iron deficiency 1
• Stool guaiac testing for occult blood 1

Treatment Approach

First-Line: Oral Iron Supplementation

Begin with oral ferrous sulfate 325 mg daily or on alternate days 3:

• Alternate-day dosing may improve tolerability with similar efficacy
• Take on an empty stomach when possible to maximize absorption
• Avoid taking with calcium, tea, coffee, or antacids which inhibit absorption 6
• Expect hemoglobin to increase by 1-2 g/dL within one month if treatment is effective 5

Common pitfall: If hemoglobin does not increase appropriately after one month, consider malabsorption, continued bleeding, or an unidentified lesion requiring further investigation 5

When to Use Intravenous Iron

Intravenous iron is indicated if you have 3, 4:

• Intolerance to oral iron (gastrointestinal side effects occur commonly)
• Malabsorption conditions (celiac disease, inflammatory bowel disease, post-bariatric surgery)
• Ongoing significant blood loss that cannot be controlled
• Chronic inflammatory conditions (chronic kidney disease, heart failure, inflammatory bowel disease, cancer)
• Pregnancy (second and third trimesters)
• Need for rapid iron repletion

Monitoring Response to Treatment

Recheck complete blood count and ferritin after 8-10 weeks of treatment 6:

• Hemoglobin should normalize
• Ferritin should rise above 30 ng/mL
• If ferritin remains low despite treatment, consider intermittent oral supplementation and monitor every 6-12 months 6

Critical warning: Do not continue long-term daily iron supplementation once ferritin normalizes, as this is potentially harmful and unnecessary 6

Special Considerations

• If you have chronic inflammatory conditions (elevated CRP), ferritin can be falsely elevated; in these cases, transferrin saturation <20% helps confirm iron deficiency even with ferritin between 30-100 ng/mL 1
• Your TIBC of 507 mg/dL translates to a transferrin saturation that is likely very low (typically <16% in iron deficiency), further confirming the diagnosis 1, 2