Final answer:
Each unit of PRBCs typically raises the hematocrit by about 3%, useful in treating conditions like anemia.
Step-by-step explanation:
Each unit of packed red blood cells (PRBCs) is generally estimated to increase the hematocrit by approximately 3%. Hematocrit measures the volume percentage of erythrocytes (red blood cells) in a blood sample. This value can vary based on numerous factors such as gender, altitude, and medical conditions. The increase in hematocrit after a transfusion helps improve the oxygen-carrying capacity of the blood, which is critical for patients with anemia or significant blood loss.