Hematocrit levels that are too high or too low can indicate a blood disorder , dehydration , or other medical conditions. A hematocrit test is often part of a complete blood count CBC , a routine test that measures different components of your blood. The test is also used to help diagnose blood disorders such as anemia , a condition in which your blood doesn't have enough red cells, or polycythemia vera, a rare disorder in which your blood has too many red cells.
Your health care provider may have ordered a hematocrit test as part of your regular checkup or if you have symptoms of a red blood cell disorder, such as anemia or polycythemia vera. These include:. A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial.
You may feel a little sting when the needle goes in or out. This usually takes less than five minutes. You don't need any special preparations for a hematocrit test. If your health care provider has ordered more tests on your blood sample, you may need to fast not eat or drink for several hours before the test. Your health care provider will let you know if there are any special instructions to follow. There is very little risk to having a hematocrit test or other type of blood test.
You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
If your results are not in the normal range, it doesn't necessarily mean that you have a medical condition requiring treatment. To learn more about your results, talk to your health care provider. Symptoms of anemia include fatigue, shortness of breath and dizziness. Symptoms of polycythemia include fatigue, itching, headaches, and sweating. Symptoms of erythrocytosis includes headaches, dizziness, shortness of breath, and nosebleeds. Hematocrit and hemoglobin measurements are both blood tests but they are not testing the same thing.
Hemoglobin is checked before each blood donation. This is to ensure that the donor has adequate red blood cell levels to donate blood. Blood donors must have a minimum of There are separate requirements for the red cell-only donation known as Power Red.
Recent studies show that there is a need for blood transfusions every 2 seconds. A hematocrit he-MAT-uh-krit test measures the proportion of red blood cells in your blood. Red blood cells carry oxygen throughout your body. Having too few or too many red blood cells can be a sign of certain diseases. A hematocrit test is part of a complete blood count CBC.
Measuring the proportion of red blood cells in your blood can help your doctor make a diagnosis or monitor your response to a treatment.
The hematocrit is a simple blood test. You won't need to fast before the test or make other preparations. The blood sample is generally drawn with a needle from a vein in your arm.
You may feel some tenderness at the site, but you'll be able to resume normal activities afterward. Results from your hematocrit test are reported as the percentage of blood cells that are red blood cells. Normal ranges vary substantially with race, age and sex. The definition of normal red-blood cell percentage also varies from one medical practice to another. Your hematocrit test provides just one piece of information about your health.
Talk to your doctor about what your hematocrit test result means in light of the symptoms you're experiencing and the results of other diagnostic tests. A number of factors can affect the outcome of a hematocrit test and yield inaccurate or misleading results, including:.
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