| A | B |
|---|
| Iron deficiency | Results from chronic blood loss |
| Vitamin B12 | Inadequate B12 is consumed |
| Pernicious | Lack of intrinsic factor which binds to B12 |
| Folic acid | Found in chronically undernourished and alcoholics |
| Hemolytic | Premature destruction of RBCs |
| Thalassemia | Alpha or Beta chains are defective. Mediterraneans and Asians. |
| G6PD | Defect in an enzyme that catalyzes glycolysis. |
| Aplastic | Bone marrow fails to produce all three types of blood cells. |
