Differential Diagnosis of Microcytic Anemia Due to Decreased Red Blood Cell Production
Diagnostic Criteria | Iron Deficiency | Iron-Transport Deficiency | Sideroblastic Iron Utilization | Chronic Disease/Inflammation |
|---|---|---|---|---|
Peripheral smear | ||||
Microcytic (M) | M | M | M, may be normocytic | Frequently normocytic |
Polychromatophilic cells | Absent | Absent | Present | Absent |
Stippled RBCs | Absent | Absent | Present | Absent |
RBCs | ||||
RBC distribution width (RDW) | ↑ | ↑ | ↑ | Normal or slightly ↑ |
Serum iron | ||||
Serum iron | ↓ | ↓ | ↑ | Normal or ↓ |
Iron-binding capacity | ↑ | ↓ | Normal | Normal or ↓ |
% Saturation of transferrin | < 10 (<15% in mild anemia) | 0 | > 50 | Normal or decreased (0–50) |
Serum ferritin | ||||
Normal, 30–300 ng/mL (67.4–674.1 pmol/L) | < 30 ng/mL (< 67.4 pmol/L) (< 100 ng/mL [< 224.7 pmol/L] if concomitant anemia of inflammation) | Usually normal | > 400 ng/mL (> 898.8 pmol/L) | > 100 ng/mL (> 224.7 pmol/L) |
Bone marrow | ||||
RBC:granulocyte ratio (normal, 1:3–1:5) | 1:1–1:2 | 1:1–1:2 | 1:1–5:1 | 1:1–1:2 |
Marrow iron | Absent | Present | ↑ | Present |
Ringed sideroblasts | Absent | Absent | Present | Absent |
RBC = red blood cell; ↑= increased; ↓= decreased. | ||||