Brain Natriuretic Peptide (BNP) Test
A brain natriuretic peptide (BNP) test measures the amount of the BNP hormone in your blood. BNP is made by your heart and shows how well your heart is working. Normally, only a low amount of BNP is found in your blood. But if your heart has to work harder than usual over a long period of time, such as from heart failure, the heart releases more BNP, increasing the blood level of BNP. The BNP level may drop when treatment for heart failure is working.
Why It Is Done
The brain natriuretic peptide (BNP) test is used to:
- Check for heart failure. A doctor may think you have heart failure if you are having problems such as trouble breathing and swelling (edema) in the arms or legs.
- Find out how severe heart failure is.
- Check the response to treatment for heart failure.
How To Prepare
You may be asked to not eat or drink anything except water for 8 to 12 hours before having a BNP test.
Your doctor may tell you to stop taking certain heart medicines before this test. Follow your doctor's instructions exactly.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
How It Is Done
The health professional drawing your blood will:
- Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
- Clean the needle site with alcohol.
- Put the needle into the vein. More than one needle stick may be needed.
- Attach a tube to the needle to fill it with blood.
- Remove the band from your arm when enough blood is collected.
- Apply a gauze pad or cotton ball over the needle site as the needle is removed.
- Apply pressure to the site and then a bandage.