Haematocrit (Hematocrit ) : packed cell volume

The term "hematocrit (HCT)" derives from the English prefix “hemato-” (relating to blood) and the Greek word “krites” (judge), essentially reflecting its function as a judge of blood composition. Hematocrit measures the volume of packed red blood cells (RBCs) as a proportion of total blood volume, hence it is also commonly referred to as packed cell volume (PCV). The hematocrit is a measure that shows what portion of blood is made up of red blood cells. It's expressed as a percentage: for men, the normal range is 40 to 54%, and for women, it’s 36 to 48%. This percentage can be measured in two ways: directly, by using a method that spins blood in a centrifuge (microhematocrit centrifugation), or indirectly, by using automated machines that calculate it. The automated method multiplies the number of red blood cells by their average size (mean cell volume, or MCV). However, because this method depends on accurately measuring the MCV, it can sometimes lead to less precise results.