Final answer:
A hematocrit test determines the ratio of the volume of packed red blood cells to that of whole blood. It measures the percentage of red blood cells (erythrocytes) in a blood sample.
Step-by-step explanation:
A hematocrit test determines the ratio of the volume of packed red blood cells to that of whole blood. It measures the percentage of red blood cells (erythrocytes) in a blood sample.
The test is performed by spinning the blood sample in a centrifuge, causing the heavier red blood cells to settle at the bottom of the tube.