BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuHematocritHCTHematocrit is a blood test that measures how much of a person's blood is made up of red blood cells. This measurement depends on the number of and size of the red blood cells.The number of and size of the red blood...An RBC count is a blood test that measures how many red blood cells (RBCs) you have. RBCs contain hemoglobin, a protein which carries oxygen. How mu...ImageRead Article Now Book Mark Article How the Test is Performed A blood sample is needed.Blood sampleVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article How to Prepare for the Test No special preparation is necessary for this test. How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed The hematocrit is almost always done as part of a complete blood count (CBC).CBCA complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...ImageRead Article Now Book Mark Article Your health care provider may recommend this test if you have signs of or are at risk for anemia. These include having:Before and after major surgery Blood in your stools, or vomit (if you throw up) Chronic medical problems, such as kidney disease or certain types of arthritis During pregnancy Fatigue, poor health, or unexplained weight loss Headaches Heavy menstrual periods Leukemia or other problems in the bone marrow Monitoring during treatment for cancer Monitoring medicines that may cause anemia or low blood counts Monitoring of anemia and its cause Poor nutrition Problems concentrating Normal Results Normal results vary, but in general they are:Male: 40.7% to 50.3% Female: 36.1% to 44.3%For babies, normal results are:Newborn: 45% to 61% Infant: 32% to 42%The examples above are common measurements for results of these tests. Normal value ranges vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results. What Abnormal Results Mean Low hematocrit may be due to:Anemia AnemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...ImageRead Article Now Book Mark Article Bleeding Bone marrow being unable to produce new red blood cells. This may be due to leukemia, other cancers, drug toxicity, radiation therapy, infection, or bone marrow disorders Chronic illness Chronic kidney disease Destruction of red blood cells (hemolysis) Leukemia Malnutrition MalnutritionMalnutrition is the condition that occurs when your body does not get enough nutrients.ImageRead Article Now Book Mark Article Too little iron, folate, vitamin B12, and vitamin B6 in the diet Too much water in the body High hematocrit may be due to:Bone marrow disease that causes abnormal increase in red blood cells (polycythemia vera) Congenital heart disease Congenital heart diseaseCongenital heart disease (CHD) is a problem with the heart's structure and function that is present at birth.ImageRead Article Now Book Mark Article Exposure to high altitude Failure of the right side of the heart Low levels of oxygen in the blood Scarring or thickening of the lungs Too little water in the body (dehydration)DehydrationDehydration occurs when your body does not have as much water and fluids as it needs. Dehydration can be mild, moderate, or severe, based on how much...ImageRead Article Now Book Mark Article Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood buildup under the skin) Infection (a slight risk any time the skin is broken) Open ReferencesReferencesChernecky CC, Berger BJ. H. Hematocrit blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:620-621.Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 124.Means RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 149.Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.AllVideoImagesTogFormed elements of blood - illustration Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.Formed elements of bloodillustrationFormed elements of blood - illustration Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.Formed elements of bloodillustration Tests for Hematocrit HematocritRelated Information RBC count(Medical Test)CBC blood test(Medical Test)Hemoglobin(Medical Test)Anemia(Condition)Multiple myeloma(Condition)Rheumatoid arthritis(Condition)Dehydration(Condition)Polycythemia vera(Condition)Anemia - InDepth(In-Depth)Rheumatoid arthritis - InDepth(In-Depth) Review Date: 1/9/2022 Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.
HematocritHCTHematocrit is a blood test that measures how much of a person's blood is made up of red blood cells. This measurement depends on the number of and size of the red blood cells.The number of and size of the red blood...An RBC count is a blood test that measures how many red blood cells (RBCs) you have. RBCs contain hemoglobin, a protein which carries oxygen. How mu...ImageRead Article Now Book Mark Article How the Test is Performed A blood sample is needed.Blood sampleVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article How to Prepare for the Test No special preparation is necessary for this test. How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed The hematocrit is almost always done as part of a complete blood count (CBC).CBCA complete blood count (CBC) test measures the following:The number of white blood cells (WBC count)The number of red blood cells (RBC count)The numb...ImageRead Article Now Book Mark Article Your health care provider may recommend this test if you have signs of or are at risk for anemia. These include having:Before and after major surgery Blood in your stools, or vomit (if you throw up) Chronic medical problems, such as kidney disease or certain types of arthritis During pregnancy Fatigue, poor health, or unexplained weight loss Headaches Heavy menstrual periods Leukemia or other problems in the bone marrow Monitoring during treatment for cancer Monitoring medicines that may cause anemia or low blood counts Monitoring of anemia and its cause Poor nutrition Problems concentrating Normal Results Normal results vary, but in general they are:Male: 40.7% to 50.3% Female: 36.1% to 44.3%For babies, normal results are:Newborn: 45% to 61% Infant: 32% to 42%The examples above are common measurements for results of these tests. Normal value ranges vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results. What Abnormal Results Mean Low hematocrit may be due to:Anemia AnemiaAnemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. Different type...ImageRead Article Now Book Mark Article Bleeding Bone marrow being unable to produce new red blood cells. This may be due to leukemia, other cancers, drug toxicity, radiation therapy, infection, or bone marrow disorders Chronic illness Chronic kidney disease Destruction of red blood cells (hemolysis) Leukemia Malnutrition MalnutritionMalnutrition is the condition that occurs when your body does not get enough nutrients.ImageRead Article Now Book Mark Article Too little iron, folate, vitamin B12, and vitamin B6 in the diet Too much water in the body High hematocrit may be due to:Bone marrow disease that causes abnormal increase in red blood cells (polycythemia vera) Congenital heart disease Congenital heart diseaseCongenital heart disease (CHD) is a problem with the heart's structure and function that is present at birth.ImageRead Article Now Book Mark Article Exposure to high altitude Failure of the right side of the heart Low levels of oxygen in the blood Scarring or thickening of the lungs Too little water in the body (dehydration)DehydrationDehydration occurs when your body does not have as much water and fluids as it needs. Dehydration can be mild, moderate, or severe, based on how much...ImageRead Article Now Book Mark Article Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Hematoma (blood buildup under the skin) Infection (a slight risk any time the skin is broken) Open ReferencesReferencesChernecky CC, Berger BJ. H. Hematocrit blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:620-621.Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 124.Means RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 149.Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.