Final answer:
The packed cell volume of red blood cells per unit of blood is known as hematocrit. Hematocrit measures the volume percentage of erythrocytes in a centrifuged blood sample and is important for diagnosing various blood conditions.
Step-by-step explanation:
The packed cell volume of red blood cells per unit of blood is known as hematocrit. A hematocrit test measures the volume percentage of erythrocytes (red blood cells) in a sample of centrifuged blood. In normal blood, erythrocytes typically make up about 45 percent of a blood sample, but this can vary slightly with normal hematocrit values for females ranging from 37 to 47 percent and males from 42 to 52 percent.
The hematocrit is an important test for diagnosing conditions like anemia or polycythemia and gives vital information about the relative proportion of red blood cells in the blood. Conditions that can be indicated by abnormal hematocrit levels include dehydration, where a high hematocrit could suggest a low plasma volume; or diseases like polycythemia vera, which cause excessive production of erythrocytes. Hematocrit is a common test conducted by spinning a blood sample in a centrifuge to separate red blood cells from the plasma.