Hematocrit is a measurement that describes the percent of red blood cells (RBCs) in a sample of whole blood.
During cancer treatment, your doctor will check your hematocrit as part of a complete blood count (CBC). A low number may indicate you have anemia, and treatments such as chemotherapy may need to be delayed until your level has increased. A high number can occur if you are dehydrated or if your body produces too many red blood cells.
The normal range of hematocrit varies depending upon age, sex, the laboratory that does the test, and altitude. The average range is 40.7 to 50.3% for an adult male and 36.1 to 44.3% for an adult female.