A hematocrit test determines which parameter?

A hematocrit test determines which parameter?

• A. Level of oxygen in the blood
• B. Packed cell volume
• C. Red blood cell count
• D. Morphology of red blood cells

Answer: (B)

Hematocrit reveals the packed cell volume—the proportion of blood that consists of red blood cells. In a hematocrit test, blood is spun in a capillary tube so the red cells pack at the bottom and plasma stays on top. The height of the red-cell layer relative to the total height of blood is read as a percentage, called the packed cell volume or hematocrit. This value reflects how much of the blood is made up of red cells, which helps assess conditions like anemia or dehydration. It does not measure how much oxygen is in the blood (that requires oxygen saturation or blood gas testing), nor does it count red blood cells per se or assess their shape; those require a RBC count or a blood smear, respectively.

Hematocrit reveals the packed cell volume—the proportion of blood that consists of red blood cells. In a hematocrit test, blood is spun in a capillary tube so the red cells pack at the bottom and plasma stays on top. The height of the red-cell layer relative to the total height of blood is read as a percentage, called the packed cell volume or hematocrit. This value reflects how much of the blood is made up of red cells, which helps assess conditions like anemia or dehydration. It does not measure how much oxygen is in the blood (that requires oxygen saturation or blood gas testing), nor does it count red blood cells per se or assess their shape; those require a RBC count or a blood smear, respectively.