The hematocrit (Ht or HCT, British English spelling haematocrit), also known as packed cell volume (PCV) or erythrocyte volume fraction (EVF), is the volume percentage (%) of red blood cells in blood.It is normally 45% for men and 40% for women.nemia refers to an abnormally low hematocrit, as opposed to polycythemia, which refers to an abnormally high hematocrit. For a condition such as anemia that goes unnoticed, one way it can be diagnosed is by measuring the hematocrit levels in the blood. Both are potentially life-threatening disorders.