Why it's doneBy Mayo Clinic staff
A hematocrit test is part of a complete blood count (CBC). The proportion of red blood cells compared with all blood cells may help your doctor make a diagnosis or monitor your response to a treatment.
A lower than normal hematocrit may indicate:
- An insufficient supply of healthy red blood cells (anemia)
- A large number of white blood cells — usually a very small portion of your blood — due to long-term illness, infection, leukemia, lymphoma or other disorders of white blood cells
- Vitamin or mineral deficiencies
- Recent or long-term blood loss
A higher than normal hematocrit may indicate:
- A disorder, such as polycythemia vera, that causes your body to produce too many red blood cells
- Fischbach FT, et al. Blood studies: Hematology and coagulation. In: Fischbach FT, et al. A Manual of Laboratory and Diagnostic Tests. 7th ed. Philadelphia, Pa.: Wolters Kluwer Health Lippincott Williams & Wilkins; 2004. http://ovidsp.ovid.com/ovidweb.cgi?T=JS&NEWS=N&PAGE=booktext&D=books&AN=00140036/7th_Edition/11&XPATH=/OVIDBOOK%5b1%5d/METADATA%5b1%5d/TBY%5b1%5d/EDITORS%5b1%5d. Accessed Dec. 13, 2010.
- Hematocrit. Lab Tests Online. http://www.labtestsonline.org/understanding/analytes/hematocrit/test.html. Accessed Dec. 13, 2010.
- Vajpayee N, et al. Basic examination of blood and bone marrow. In: McPherson RA, et al. Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa.: Saunders Elsevier; 2007. http://www.mdconsult.com/books/page.do?eid=4-u1.0-B1-4160-0287-1..50033-1--cesec2&isbn=1-4160-0287-1&sid=1095295726&type=bookPage§ionEid=4-u1.0-B1-4160-0287-1..50033-1--cesec23&uniqId=230035913-3#4-u1.0-B1-4160-0287-1..50033-1--cesec23. Accessed Dec. 13, 2010.
- Laboratory reference values. Hematocrit. Rochester, Minn.: Mayo Foundation for Medical Education and Research; 2010.