Which laboratory finding is indicative of Iron Deficiency Anemia?

In the context of iron deficiency anemia, low serum iron is a key laboratory finding. Iron deficiency anemia occurs when the body lacks sufficient iron to produce hemoglobin, the protein in red blood cells that carries oxygen. As a result, serum iron levels drop, reflecting the deficiency of available iron in the bloodstream.

Serum iron is measured to assess the amount of iron present in the circulation. In cases of iron deficiency anemia, the body's iron stores are depleted, leading to a reduced serum iron level. This low level is typically accompanied by other findings, such as low ferritin, which indicates decreased stored iron, and increased total iron-binding capacity (TIBC), reflecting the body's attempt to compensate for the low iron availability.

In contrast, high serum ferritin and high serum iron would indicate either sufficient or excess iron, which is not consistent with iron deficiency anemia. Furthermore, low TIBC is typically observed in situations where iron overload or inflammation is present, rather than in deficiency states. Therefore, low serum iron directly aligns with the pathophysiological changes that occur in iron deficiency anemia, making it the correct answer in this case.