|
Figure 27 Differential diagnosis of microcytic anemia.
TIBC, Total iron binding capacity.
Modified and updated from Rakel RE [ed]: Principles of family practice, ed 7, Philadelphia, 2007, Saunders.
Table 10 Differential Diagnosis of Microcytic Hypochromic Anemia
| Parameter | Iron-Deficiency Anemia | Anemia of Chronic Disease (Anemia of Inflammation) | Thalassemias | Sideroblastic Anemia |
|---|---|---|---|---|
| MCV | ↓ | ↓/ N | ↓ | ↓/ N |
| Serum iron | ↓ | ↓ | N | ↑ |
| Transferrin saturation | ↓ | ↓/ N | N | ↑ |
| TIBC | ↓ | ↓/ N | N | N |
| Serum transferrin receptor | ↑ | ↓ | N | N / ↑ |
| Serum ferritin | ↓ | ↑/ N | N | ↑ |
| Serum hepcidin | ↓ | ↑ | N / ↓ | ↓ |
| Bone marrow iron stores | ↓ | ↑/ N | ↑/ N | ↑/ N Ring sideroblasts |
MCV, Mean cell volume; N, normal; TIBC, total iron-binding capacity.
Talley NJ et al: Essentials of internal medicine, ed 4, Chatswood, NSW, 2021, Elsevier Australia.
Table 11 Stages in the Development of Iron Deficiency Anemia
| Hemoglobin (g/dL) | Peripheral Smear | Serum Iron (μg/dL) | Bone Marrow Iron | Serum Ferritin (ng/ml) |
|---|---|---|---|---|
| 13+ (normal) | nc/nc | 50-150 | Fe2+ | Male: 40-340 Female: 40-150 |
| 10-12 | nc/nc | ↓ | Fe2+ absent, erythroid hyperplasia | <12 |
| 8-10 | hypo/nc | ↓ | Fe2+ absent, erythroid hyperplasia | <12 |
| <8 | hypo/micro∗ | ↓ | Fe2+ absent, erythroid hyperplasia | <12 |
Hypo/micro, Hypochromic, microcytic; hypo/nc, hypochromic, normocytic; nc/nc, normochromic, normocytic.
∗Microcytosis, determined by a mean corpuscular volume (in fL) <2 standard deviations (SD) below the mean, must be adjusted for age (e.g., -2 SD at 3-6 mo = 74; at 0.5-2 yr = 70; at 2-6 yr = 75; at 6-12 yr = 77; and at 12-18 yr = 78).
From Andreoli TE et al: Cecil essentials of medicine, ed 4, Philadelphia, 1997, Saunders.
Box 9 Causes of Iron Deficiency
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From Talley NJ et al: Essentials of internal medicine, ed 4, Chatswood, NSW, 2021, Elsevier Australia.