How to treat an adolescent girl with normal hemoglobin (Hb) levels but low iron indices, previously having slightly low hemoglobin?

Treatment of Iron Deficiency Without Anemia in an Adolescent Girl

This adolescent girl has iron deficiency without anemia and should be treated with oral iron supplementation at 60-120 mg of elemental iron daily for at least 3 months to replenish iron stores, combined with dietary counseling. 1, 2

Why Treatment is Necessary

Even though her hemoglobin has normalized, the low iron indices indicate depleted iron stores that require treatment. Iron deficiency at all levels—including non-anemic iron deficiency—should be treated because iron is essential for optimal cognitive function, physical performance, and serves as a critical constituent of many enzymes beyond just oxygen transport. 3 Adolescent females are at particularly high risk for iron deficiency due to menstrual blood loss and increased iron requirements during growth. 4, 1

Recommended Treatment Regimen

Oral Iron Supplementation

• Prescribe 60-120 mg of elemental iron daily (the standard dose for adolescent girls), typically given as ferrous sulfate 200 mg once or twice daily. 4, 1, 2
• Administer iron on an empty stomach or between meals to maximize absorption, ideally in the morning. 5, 3
• If gastrointestinal side effects occur (nausea, constipation, black stools), the iron can be taken with meals despite reduced absorption, or consider switching to a different formulation such as ferrous gluconate or ferrous fumarate which may be better tolerated. 4, 6
• Continue treatment for at least 3 months to adequately replenish iron stores, even after hemoglobin and iron indices normalize. 1, 2, 5

Enhancing Iron Absorption

• Recommend vitamin C (250-500 mg) with iron supplementation or vitamin C-rich foods to enhance absorption. 4, 1
• Counsel on consuming iron-rich foods, particularly heme iron from meat sources which has superior bioavailability compared to plant-based non-heme iron. 1, 2
• Advise avoiding calcium supplements, tea, coffee, and dairy products within 2 hours of iron administration as these inhibit absorption. 6, 5

Monitoring Response to Treatment

• Recheck hemoglobin and iron indices after 8-10 weeks of treatment to confirm adequate response. 3
• If no improvement occurs despite documented compliance, obtain additional testing including mean corpuscular volume (MCV), red blood cell distribution width (RDW), and repeat serum ferritin to rule out other causes of microcytosis such as thalassemia trait. 1, 2
• After successful treatment, reassess hemoglobin approximately 6 months later and consider annual screening given her risk factors as an adolescent female. 4, 1

Identifying and Addressing Underlying Causes

Evaluate for potential causes of iron depletion in this adolescent:

• Heavy or prolonged menstrual bleeding (affects approximately 10% of women of childbearing age). 4
• Inadequate dietary iron intake, particularly if following vegetarian/vegan diet, restrictive eating patterns, or disordered eating habits. 1, 5
• High-level athletic activity which increases iron requirements. 1
• Chronic health conditions affecting iron absorption such as inflammatory bowel disease or celiac disease. 5

Common Pitfalls to Avoid

• Do not discontinue iron therapy as soon as hemoglobin normalizes—stores must be replenished which requires at least 3 months of continued treatment. 1, 2
• Do not assume parenteral iron is necessary—oral iron is first-line therapy and parenteral iron should only be considered for intolerance to at least two oral preparations, documented non-compliance, or malabsorption conditions. 4, 1
• Do not provide preventative iron supplementation if stores become normal—long-term daily iron supplementation in the presence of normal or high ferritin values is potentially harmful. 3
• Warn the patient that occasional gastrointestinal discomfort and black stools are common side effects but not dangerous. 6