HCT is the erythrocyte specific product, with normal values ranging from 40%-50% in men and 37%-38% in women. HCT is the volume of red blood cells per liter of blood. when HCT is elevated, the number of red blood cells is relatively increased, often seen in dehydration, where a decrease in water in the blood makes the red blood cells relatively concentrated, leading to an increase in HCT. a decrease in HCT is often seen in a decrease in the base number of red blood cells, such as anemia or massive blood dilution. When water intoxication or excessive clinical rehydration occurs, this can also lead to a decrease in HCT. Therefore, HCT is a reference indicator of the number of red blood cells in the blood and is influenced by the amount of water in the blood as well as the number of red blood cells themselves. It is important to analyze HCT indicators in the context of the clinical situation and the patient’s specific situation.