Understand that hematocrit is a measure related to blood composition.
Recognize that hematocrit specifically measures the proportion of blood volume that is occupied by red blood cells.
Differentiate between hematocrit and other blood measurements such as hemoglobin concentration, which measures the amount of hemoglobin in the blood, and white blood cell count, which measures the number of white blood cells.
Acknowledge that hematocrit is expressed as a percentage, indicating the volume of red blood cells relative to the total blood volume.
Conclude that hematocrit does not measure the total volume of blood in the body, but rather the percentage of red blood cells within that volume.