Which of the following is a biochemical characteristic of anemia?

Anemia is characterized by a deficiency in red blood cells or hemoglobin in the blood, which results in a reduced ability to transport oxygen throughout the body. A biochemical characteristic of anemia includes a decrease in circulated red blood cells (RBC), a decrease in hemoglobin levels, and a reduction in packed red cell volume.

Each of these components plays a crucial role in diagnosing and understanding anemia. When the number of circulating RBCs decreases, there are fewer cells available to transport oxygen, leading to potential fatigue and weakness in affected individuals. Similarly, a decrease in hemoglobin — the protein in RBCs responsible for binding and carrying oxygen — directly impacts the oxygen-carrying capacity of the blood. Additionally, a reduction in packed red cell volume indicates a lower proportion of red blood cells in relation to plasma, which is another vital aspect of how anemia manifests in the body.

Since all of these factors are interconnected and help define and diagnose anemia, the correct answer encompasses all of them collectively.