The percentage of red blood cells in the blood is called which term?

• A. crit
• B. hematocrit
• C. All of these
• D. PCV

Answer: (C)

The main idea is that several terms describe the same fraction of blood: the portion that is made up of red blood cells. This percentage is known as hematocrit, and packed cell volume (PCV) is just another name for the same measurement. Crit is also used in some contexts to mean the same thing. Because all three terms describe the same RBC fraction of whole blood, they are all correct descriptors of this measurement.

How it’s measured helps you understand why these terms are equivalent: blood is collected, usually in a capillary tube with anticoagulant, and then centrifuged. The red blood cells pack at the bottom, and the height of that packed cell layer as a percentage of the total blood column gives the hematocrit (or PCV). Clinically, this value helps assess anemia, polycythemia, and hydration status. It’s important to remember that the value reflects volume fraction, not the total number of red cells, so it’s interpreted alongside other measures like hemoglobin and total red cell mass.