Blood Disorders Anemia Hematocrit Level Test Print By Amber J. Tresca | Medically reviewed by a board-certified physician Updated December 07, 2017 A hematocrit test can tell your physician important information about your red blood cells. Image © More in Blood Disorders Anemia Iron Deficiency Anemia Inherited Anemias White Blood Cell Disorders Polycythemia Vera & Myelofibrosis Human blood contains 3 components: red blood cells, white blood cells, and platelets. A hematocrit (HCT) test measures the volume of the red blood cells in a specified amount of blood. Hematocrit is calculated in a lab from a blood sample taken from a patient and is expressed as a percentage. This test is usually ordered as part of a complete blood count (CBC) test. A physician may order the CBC, which includes the hematocrit if a patient is suspected of having anemia, leukemia, or certain nutritional deficiencies. What Is the Normal Range of Hematocrit? Hematocrit is calculated in a lab from a sample of blood. Both the number and the size of the red blood cells in the sample will affect the volume of the red blood cells. Different labs will have their own definition of a normal range for a hematocrit level, therefore the normal ranges given in the table below are only one possible example. This test is not specific enough to diagnose any particular disease or disorder, but instead is a tool that can be used in the diagnostic process. If you have questions about your hematocrit level and what it means to your health, consult with your physician. Example Hematocrit Level Reference Ranges Approximate Range for Women 38% to 46% Approximate Range for Men 42% to 54% Expressed as a percentage of whole blood Why Is a Hematocrit Test Done? Many factors can affect hematocrit level, including bleeding and bone marrow conditions. Dehydration may suggest a falsely high hematocrit level, which will need to be taken into consideration for those patients that are affected. A patient who has a low hematocrit level has anemia. Conditions that may be associated with a low hematocrit level are: BleedingLack of folate, iron, or vitamin B12LeukemiaSide effect of chemotherapy drugs Conditions that may be associated with a high hematocrit level: DehydrationHeart diseaseLung disease (such as hypoxia)Polycythemia vera Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you reach your 2018 goals. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Continue Reading