Mild Iron Deficiency Anemia with Early Iron-Deficient Erythropoiesis
This patient has early iron deficiency anemia that requires iron supplementation and investigation for the underlying cause, as the low MCH (26.4 pg) and low MCHC (30.9 g/dL) indicate iron-deficient red cell production even though the hemoglobin is only mildly reduced. 1
Clinical Significance of the Laboratory Pattern
The combination of findings reveals evolving iron deficiency:
Low MCH (26.4 pg, reference 26.6-33.0) is the most sensitive early marker of iron deficiency, as it reflects reduced hemoglobin content in newly produced red cells and is more reliable than MCHC for detecting iron-deficient erythropoiesis 1
Low MCHC (30.9 g/dL, reference 31.5-35.7) confirms hypochromia, indicating that red cells contain less hemoglobin per unit volume than normal, which strongly suggests iron deficiency 1, 2
Normal MCV (86 fL) does not exclude iron deficiency, as microcytosis develops later in the progression of iron deficiency; the bone marrow initially produces normocytic but hypochromic cells 1
Hemoglobin of 11.6 g/dL meets WHO criteria for anemia in non-pregnant women (threshold <12 g/dL), though it represents mild anemia 3, 1
Required Diagnostic Workup
Obtain iron studies immediately to confirm iron deficiency and guide treatment:
Serum ferritin is the single most useful test, with levels <30 μg/L confirming iron deficiency in the absence of inflammation 3, 1
Transferrin saturation <15-16% supports iron deficiency and is less affected by acute inflammation than ferritin 3, 1
Measure C-reactive protein (CRP) or ESR to assess for inflammation, as ferritin can be falsely elevated (up to 100 μg/L) in inflammatory states, potentially masking true iron deficiency 3, 1
If inflammation is present (elevated CRP/ESR), ferritin between 30-100 μg/L with transferrin saturation <16% indicates likely iron deficiency, and ferritin should be >100 μg/L to exclude iron deficiency in this context 3
Reticulocyte count helps evaluate bone marrow response to anemia 1
Investigation for Underlying Cause
All adult women with confirmed iron deficiency require evaluation for the source of blood loss:
In premenopausal women, menstrual blood loss is the most common cause, but gastrointestinal sources must be considered if menstrual losses seem inadequate to explain the deficiency 3
Assess for gastrointestinal blood loss by taking a careful history of NSAID use, gastrointestinal symptoms, and dietary factors 3
Consider celiac disease screening with tissue transglutaminase (tTG) antibody testing, as malabsorption is an important cause of iron deficiency (approximately 5% prevalence in iron deficiency anemia) 3
Gastrointestinal endoscopy may be warranted if iron deficiency is confirmed and no other obvious source is identified, particularly if the patient has gastrointestinal symptoms or risk factors 3
Treatment Approach
Iron supplementation should be initiated once iron deficiency is confirmed:
Oral iron supplementation is first-line therapy for patients with mild anemia (Hb >10 g/dL), typically 100 mg elemental iron daily 3
Parenteral (intravenous) iron should be considered if oral iron is not tolerated due to gastrointestinal side effects (nausea, constipation, diarrhea), if there is malabsorption, or if rapid repletion is needed 3
Intramuscular iron should be avoided as there is no evidence it is safer or more effective than oral or intravenous routes 3
Blood transfusion is not indicated for this patient, as it should be reserved for symptomatic anemia with cardiovascular instability (fatigue, hypotension, tachycardia) 3
Monitoring and Follow-up
Regular monitoring ensures treatment response and detects recurrence:
Recheck hemoglobin and iron studies after 1-3 months of iron supplementation to assess response 1
Monitor for recurrence, as anemia recurs in >50% of patients within one year, often indicating ongoing blood loss or inadequate iron stores 3
Continue iron supplementation for 3-6 months after hemoglobin normalizes to replenish body iron stores 3
Critical Pitfalls to Avoid
Do not dismiss this as "borderline normal" – the low MCH and MCHC indicate active iron-deficient erythropoiesis that will progress to more severe anemia without treatment 1
Do not rely on MCV alone – iron deficiency can exist with normal MCV, and MCH is more sensitive for early detection 1
Do not interpret ferritin in isolation – always assess inflammatory markers, as inflammation falsely elevates ferritin and can mask iron deficiency 3, 1
Do not assume menstruation explains all iron deficiency in premenopausal women – consider gastrointestinal pathology if iron deficiency is severe or recurrent 3