Hematocrit measures the percentage of blood volume made up by which component?

• A. Red Blood Cells
• B. Hematocrit
• C. Platelets
• D. White Blood Cells

Answer: (B)

Hematocrit measures the portion of blood volume occupied by red blood cells. When blood is separated, red blood cells settle to the bottom, and the height of that red-cell layer relative to the total blood column is expressed as a percentage. This value reflects the blood’s oxygen-carrying capacity and helps detect conditions like anemia or polycythemia. The other components, white blood cells and platelets, are not what hematocrit quantifies, so the correct idea is that red blood cells make up the measured component.