Iron deficiency anemia is characterized by which of the following?

Iron deficiency anemia is primarily characterized by a decrease in the availability of iron in the body, which directly affects the production of hemoglobin and red blood cells. Therefore, one key feature of this condition is the decreased plasma iron level, which indicates that there is less iron available for the production of red blood cells.

Additionally, in iron deficiency anemia, the percentage saturation of transferrin, which is the plasma protein responsible for transporting iron, is decreased. This occurs because there's less iron available to bind to transferrin, leading to a lower percentage saturation.

Another hallmark of iron deficiency anemia is an increase in total iron-binding capacity (TIBC). When iron stores are low, the liver increases the production of transferrin to maximize the body's ability to capture any available iron. Hence, a high TIBC value indicates an adaptive response of the body to try to capture more iron in the setting of iron deficiency.

In summary, the correct answer encapsulates these essential characteristics of iron deficiency anemia: decreased plasma iron, decreased % saturation of transferrin, and increased TIBC, reflecting the physiological adjustments occurring due to insufficient iron levels.