Laboratory Interpretation: Microcytic Hypochromic Anemia with Iron Deficiency
These laboratory values indicate microcytic hypochromic anemia that requires immediate iron studies (serum ferritin as first-line test) to confirm iron deficiency, followed by investigation for the underlying cause, particularly gastrointestinal pathology.
Key Abnormalities Identified
Anemia Present
- Hemoglobin 10.4 g/dL is below the WHO-defined threshold (<13.0 g/dL for men, <12.0 g/dL for non-pregnant women) 1
- Hematocrit 34.4% is proportionally reduced
Microcytic Hypochromic Pattern
- MCV 80.4 fL indicates microcytosis (reduced red cell size)
- MCH 24.3 pg indicates hypochromia (reduced hemoglobin per cell) - this is the more reliable marker for iron deficiency 1
- MCHC 30.2 g/dL is reduced, confirming hypochromia
- RDW 15.6% is elevated, indicating anisocytosis (variable red cell sizes)
The combination of low MCV, low MCH, low MCHC, and elevated RDW strongly suggests iron deficiency anemia 1.
Other Findings
- Platelets 419 × 10⁹/L are elevated (reactive thrombocytosis, common in iron deficiency)
- AST 9 U/L is normal to low (no hepatic concern)
- Albumin 3.5 g/dL is at lower limit of normal (rules out severe malnutrition/inflammation as primary cause)
Immediate Next Steps
1. Confirm Iron Deficiency
Order serum ferritin immediately - this is the single most useful marker 1:
- <15 μg/L = definitive iron deficiency (specificity 0.99)
- <30 μg/L = low iron stores
- <45 μg/L = warrants investigation even with inflammation present 1
If ferritin is equivocal (30-45 μg/L range), add:
- Transferrin saturation
- Consider soluble transferrin receptor if inflammation suspected 1
2. Investigate the Cause
At any level of anemia with confirmed iron deficiency, investigation should be considered 1. The British Society of Gastroenterology guidelines emphasize that waiting for more severe anemia (Hb <11.0 g/dL in men, <10.0 g/dL in women) will miss cases of colorectal cancer 1.
Critical pitfall: MCH is more reliable than MCV for detecting iron deficiency because it's less affected by storage conditions and concurrent conditions 1. Your patient's MCH of 24.3 pg is significantly reduced.
3. Rule Out Alternative Diagnoses
Before attributing microcytosis solely to iron deficiency:
- If iron studies are normal with microcytosis: Order hemoglobin electrophoresis to exclude thalassemia, particularly if appropriate ethnic background 1
- Thalassemia typically shows MCV reduced out of proportion to anemia severity 1
4. Therapeutic Trial
If iron deficiency is confirmed, initiate iron therapy and reassess:
- A hemoglobin rise ≥10 g/L within 2 weeks is highly suggestive of absolute iron deficiency, even if initial iron studies were equivocal 1
Clinical Significance
The elevated RDW (15.6%) combined with microcytosis indicates a heterogeneous red cell population, typical of evolving iron deficiency where newer cells are more microcytic than older ones 2. This pattern, along with reactive thrombocytosis, strongly supports iron deficiency as the primary diagnosis.
The normal albumin and AST argue against chronic inflammatory disease or severe liver pathology as confounding factors, making ferritin interpretation more straightforward 1.