how do they test hematocrit
The hematocrit is the proportion, by volume, of the blood that consists of red blood cells. The hematocrit (hct) is expressed as a percentage. For example, a hematocrit of 25% means that there are 25 milliliters of red blood cells in 100 milliliters of blood. The hematocrit is typically measured from a blood sample by an automated machine that makes several other measurements of the blood at the same time.
Hematocrit (Hct) Levels. This is the ratio of the volume of red cells to the volume of whole blood. Normal range for hematocrit is different between the sexes and is approximately 45% to 52% for men and 37% to 48% for women. This is usually measured by spinning down a sample of blood in a test tube, which causes the red blood cells to pack at the bottom of the tube.