Differential Diagnosis for Low Hemoglobin, MCH, MCHC, and High RDW

Single Most Likely Diagnosis

• Iron Deficiency Anemia: This is the most common cause of low hemoglobin, MCH (mean corpuscular hemoglobin), and MCHC (mean corpuscular hemoglobin concentration) with a high RDW (red cell distribution width). The high RDW indicates a variation in red blood cell size, which is typical in iron deficiency anemia due to the gradual depletion of iron stores affecting hemoglobin synthesis and leading to smaller (microcytic) and more varied red blood cells.

Other Likely Diagnoses

• Thalassemia: These are genetic disorders affecting hemoglobin synthesis, leading to microcytic anemia with low MCH and MCHC. While RDW can be elevated, it's often less pronounced than in iron deficiency anemia. However, thalassemia trait or minor forms can present with similar laboratory findings.
• Chronic Disease Anemia: Conditions like chronic kidney disease, rheumatoid arthritis, or other chronic inflammatory diseases can lead to anemia of chronic disease, which may present with low hemoglobin, MCH, and MCHC, and an elevated RDW due to the body's impaired ability to utilize iron for erythropoiesis.
• Sideroblastic Anemia: This group of disorders is characterized by the presence of ringed sideroblasts in the bone marrow and can be congenital or acquired. It leads to microcytic anemia with variable RDW elevation.

Do Not Miss Diagnoses

• Anisocytosis due to Mixed Anemia: A combination of iron deficiency and another anemia type (e.g., vitamin deficiency anemia) can lead to a high RDW. Missing one component of the mixed anemia could lead to inadequate treatment.
• Myelodysplastic Syndromes (MDS): These are clonal stem cell disorders that can present with anemia, often with a high RDW due to the dysplastic nature of the erythropoiesis. MDS can progress to acute myeloid leukemia, making early diagnosis critical.

Rare Diagnoses

• Congenital Dyserythropoietic Anemias: These are rare genetic disorders affecting erythropoiesis, leading to anemia with distinct morphological features on bone marrow examination.
• Hemoglobinopathies: Certain hemoglobinopathies, like hemoglobin E disease, can present with microcytic anemia and elevated RDW, though they are less common in populations not endemic to Southeast Asia.
• Lead Poisoning: Can cause microcytic anemia with basophilic stippling of red blood cells and may elevate RDW, though it's relatively rare and usually associated with specific exposure histories.