Hematocrit Test
Reviewed
Also called: Packed cell volume, PCV, Crit, H and H (Hemoglobin and Hematocrit)
A hematocrit test is a blood test that measures the amount (percent) of your blood that is made up of red blood cells.
Specimen: blood
Why this test may be ordered
- As part of a routine checkup
- To monitor health if you are being treated for cancer or have an ongoing health condition
- If you have symptoms of anemia, such as shortness of breath, weakness, fatigue, headache, dizziness, or arrhythmia
- If you have symptoms of polycythemia, such as headache, feeling light-headed, shortness of breath when lying down, weakness, skin itching after a shower, blurred vision, or unusual bleeding
Preparation and collection
You don't need any special preparations for a hematocrit test. If your provider has ordered more tests on your blood sample, you may need to fast (not eat or drink) for several hours before the test.
A health care professional will take a blood sample from a vein in your arm, using a small needle. This usually takes less than five minutes.
There is very little risk to a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
Your hematocrit test results are reported as a number. That number is the percentage of your blood that's made up of red blood cells. Normal hematocrit levels will vary, depending on your sex, age, whether or not you smoke, and the altitude where you live.
- Lower than normal: A lower-than-normal hematocrit level may be a sign that: You have had blood loss due to a recent injury, You have a condition causing chronic (long-term) blood loss, Your body doesn't have enough red blood cells (anemia). Limitation: Pregnancy can cause a low hematocrit. Next step: To learn what your test results mean, talk with your provider.
- Higher than normal: A higher-than-normal hematocrit level may be a sign that: Your body is making too many red blood cells, which may be caused by: Lung disease, Congenital heart disease, Heart failure, Polycythemia. Limitation: Living at high altitudes with less oxygen in the air may cause a high hematocrit. Next step: Ask your provider what your hematocrit level should be.
- Normal hematocrit levels vary depending on your sex, age, whether or not you smoke, and the altitude where you live.
- Pregnancy can cause a low hematocrit because your body has more fluid than usual, which decreases the percentage of red blood cells.
- Living at high altitudes with less oxygen in the air may cause a high hematocrit.
- If your results are not in the normal range, it doesn't always mean you have a medical condition that needs treatment.
- Interpretation of results should be done by your healthcare provider.
What to do next
To learn what your test results mean, talk with your provider.
- What is my hematocrit level and what does it mean for my health?
- Do I need any follow-up tests based on my hematocrit result?
- Could my medications or other health conditions affect my hematocrit level?
- How often should I have my hematocrit checked?
- What symptoms should I watch for that might indicate a change in my red blood cell levels?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.