Hematocrit | |
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MeSH | D006400 |
MedlinePlus | 003646 |
The hematocrit (/hɪˈmætəkrɪt/) (Ht or HCT), also known by several other names, is the volume percentage (vol%) of red blood cells (RBCs) in blood,[1][2] measured as part of a blood test.[3] The measurement depends on the number and size of red blood cells.[3] It is normally 40.7–50.3% for males and 36.1–44.3% for females.[3] It is a part of a person's complete blood count results,[4] along with hemoglobin concentration, white blood cell count and platelet count.
Because the purpose of red blood cells is to transfer oxygen from the lungs to body tissues, a blood sample's hematocrit—the red blood cell volume percentage—can become a point of reference of its capability of delivering oxygen. Hematocrit levels that are too high or too low can indicate a blood disorder, dehydration, or other medical conditions.[4] An abnormally low hematocrit may suggest anemia, a decrease in the total amount of red blood cells, while an abnormally high hematocrit is called polycythemia.[5] Both are potentially life-threatening disorders.