The pathophysiologic classification system of anemia is divided into two broad categories. These categories are based on the underlying cause of the decrease in RBCs in circulation. The categories are:
- Anemia caused by decreased production of RBCs
- Anemia caused by increased destruction or loss of RBCs
Destruction of RBCs after release from the bone marrow occurs due to either an intracorpuscular abnormality or an extracorpuscular abnormality. Intracorpuscular abnormalities result from an abnormality in the red cell membrane, an enzyme, or a globin chain (inherited condition). Extracorpuscular abnormalities are secondary to a clinical condition (acquired condition).
The tables below summarize the pathophysiologic classification of anemia and provide examples in each category.
Table 5. Anemias Due to Decreased Production.| Category | Inherited or Acquired | Anemia |
| Defective stem cell proliferation | Acquired | Aplastic Anemia |
| Interruption of DNA synthesis | Acquired | Megaloblastic Anemia |
| Interruption of hemoglobin synthesis | Acquired or inherited | Iron deficiency Thalassemia |
| Interruption of development of precursor cells | Acquired or inherited | Anemia of chronic renal disease, Anemia associated with endocrine diseases |
Table 6. Anemias Due to Increased Destruction or Loss (Intracorpuscular Abnormalities).| Category | Inherited or Acquired | Anemia |
| Membrane defect | Inherited | Hereditary spherocytosis, hereditary elliptocytosis |
| Enzyme deficiency | Inherited | G-6-PD deficiency, Pyruvate kinase deficiency |
| Globin abnormality - Hemoglobinopathy | Inherited | Sickle cell anemia, Hemoglobin C anemia |
| Complement related | Acquired | Paroxysmal nocturnal hemoglobinuria |
Table 7. Anemias Due to Increased Destruction or Loss (Extracorpuscular Abnormalities).| Category | Inherited or Acquired | Anemia |
| Mechanical | Acquired | Microangiopathic hemolytic anemias |
| Infection | Acquired | Babesia, Malaria, E. coli spesis |
| Chemical or physical agents | Acquired | Drugs, toxins, burns |
| Antibody-mediated | Acquired | Warm autoimmune hemolytic anemia |
