Which statement correctly describes hematocrit and packed cell volume?

Which statement correctly describes hematocrit and packed cell volume?

• A. Packed cell volume is another term for hematocrit
• B. Hematocrit is used to measure plasma proteins
• C. Packed cell volume is measured in liters per liter
• D. Hematocrit and packed cell volume measure different things

Answer: (A)

Hematocrit and packed cell volume describe the same measurement—the proportion of blood volume that is made up of red blood cells. To determine it, you centrifuge a blood sample so the red cells form a packed column at the bottom and the plasma stays above. The height of the red cell layer divided by the total height of the blood column gives the percentage of red cells, which is how this value is reported. In practice, PCV is the term often used in veterinary labs, while hematocrit is the term more common in human medicine, but they refer to the same concept. This is why the statement is the best choice: packed cell volume is another term for hematocrit. It’s not a measure of plasma proteins (that’s a different test), and the result is not given in liters per liter in routine practice (it’s expressed as a percentage, or a decimal fraction), and they do not measure different things.

Hematocrit and packed cell volume describe the same measurement—the proportion of blood volume that is made up of red blood cells. To determine it, you centrifuge a blood sample so the red cells form a packed column at the bottom and the plasma stays above. The height of the red cell layer divided by the total height of the blood column gives the percentage of red cells, which is how this value is reported. In practice, PCV is the term often used in veterinary labs, while hematocrit is the term more common in human medicine, but they refer to the same concept.

This is why the statement is the best choice: packed cell volume is another term for hematocrit. It’s not a measure of plasma proteins (that’s a different test), and the result is not given in liters per liter in routine practice (it’s expressed as a percentage, or a decimal fraction), and they do not measure different things.