Iron Deficiency Anemia in a 15-Year-Old Female
This 15-year-old female has iron deficiency anemia (IDA), and she should begin oral ferrous sulfate 200 mg (65 mg elemental iron) three times daily immediately. 1
Diagnostic Confirmation
The laboratory findings definitively establish iron deficiency anemia:
- Microcytic hypochromic anemia with MCV 66.2 fL (markedly below normal 80 fL threshold), MCH 20.8 pg, and 2+ hypochromasia and microcytosis on peripheral smear 2, 3
- Low serum iron of 45 µg/dL confirms inadequate iron availability 3, 1
- Elevated RDW of 16.6% (>14%) indicates increased red cell size variation, which strongly supports IDA rather than thalassemia trait when combined with low MCV 3, 4
- Serum ferritin should be obtained if not already done, as it is the single most useful marker for confirming iron deficiency, with levels <15 µg/L being diagnostic 2, 1
The combination of low MCV, low MCH, elevated RDW >14%, and low serum iron creates a pattern that strongly distinguishes IDA from thalassemia trait, which typically shows normal RDW 3, 4.
Immediate Treatment Protocol
Start oral iron supplementation now:
- Ferrous sulfate 200 mg (65 mg elemental iron) three times daily is first-line therapy and most cost-effective 1
- Alternative dosing: 3-6 mg/kg/day of elemental iron if the standard dose is not tolerated 1, 5
- Add vitamin C (ascorbic acid) to enhance iron absorption 1
- Encourage heme iron from meat sources over plant-based non-heme iron for better absorption 1
Monitoring Response
Follow-up schedule:
- Check hemoglobin at 2 weeks to confirm response (expect ≥10 g/L rise, which confirms IDA even if initial iron studies were equivocal) 2, 1
- Monitor hemoglobin every 3 months for one year, then annually 1
- Continue iron therapy for 3 months after anemia correction to replenish iron stores 1
Identify Underlying Cause
In adolescent females, the most common causes are:
- Menstrual blood loss (most common in this age group) 1
- Inadequate dietary iron intake 1
- Increased physiological demands from growth and athletic activity 1
Evaluate for:
- Menstrual history (heavy or prolonged periods)
- Dietary assessment (vegetarian diet, inadequate meat intake)
- Athletic participation
- Gastrointestinal symptoms suggesting malabsorption or bleeding 2
When to Consider Alternative Therapy
Parenteral iron is reserved for:
- Intolerance to at least two oral iron preparations
- Non-compliance with oral therapy
- Intestinal malabsorption
- Anemia refractory to oral supplementation 1
Critical Pitfalls to Avoid
Do not delay treatment while waiting for ferritin results—the clinical picture is diagnostic, and a good response to iron therapy (Hb rise ≥10 g/L within 2 weeks) confirms IDA retrospectively 2.
Do not perform hemoglobin electrophoresis in this case—the elevated RDW >14% with microcytosis indicates IDA, not thalassemia trait, which typically shows normal RDW 3, 4. Hemoglobin electrophoresis is only indicated when microcytosis occurs with normal iron studies 2.
Do not stop iron therapy when hemoglobin normalizes—continue for 3 additional months to replenish iron stores 1.