Brain natriutetic peptide (BNP) test is a blood test that measures levels of a protein made by your heart and blood vessels. This protein is called BNP. BNP levels are higher than normal when you have heart failure.
How the test is performed
A blood sample is needed. For information on how this is done, see:
This test is usually done in the emergency room or hospital. Results take up to 15 minutes. In some hospitals, a finger prick test with rapid results is available.
How the test will feel
When the needle is inserted to draw blood, you may feel moderate pain, though most people feel only a prick or a stinging sensation. Afterward there may be some throbbing or bruising.
Why the test is performed
Your doctor may order this test if you have signs of heart failure. Symptoms include shortness of breath and swelling of your legs or abdomen. The test helps your doctor make sure the problems are due to your heart and not your lungs, kidneys, or liver.
It is unclear if repeated BNP tests are helpful in guiding treatment in those already diagnosed with heart failure.
In general, results less than 100pg/mL are a sign the patient does not have heart failure.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
BNP levels go up when the heart cannot pump the way it should.
A result greater than 100 pg/mL is abnormal. The higher the number, the more likely heart failure is present and the more severe it is.
What the risks are
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood 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 light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
A related test, called the N-terminal pro-BNP test, is done in the same way. It provides similar information to your health care provider.