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
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
- Check the response to treatment for heart
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
- 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
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
- Remove the band from your arm when enough blood is
- Apply a gauze pad or cotton ball over the needle site as
the needle is removed.
- Apply pressure to the site and then a
How It Feels
You may feel nothing at all from the
needle puncture, or you may feel a brief sting or pinch as the needle goes
through the skin. Some people feel a stinging pain while the needle is in the
vein. But many people do not feel any pain (or have only minor discomfort) once
the needle is positioned in the vein. The amount of pain you feel depends on
the skill of the health professional drawing the blood, the condition of your
veins, and your sensitivity to pain.
There is very little risk of complications from
having blood drawn from a vein.
- You may develop a small bruise at the puncture
site. You can reduce the risk of bruising by keeping pressure on the site for
several minutes after the needle is withdrawn.
- In rare cases, the
vein may become inflamed after the blood sample is taken. This condition is
called phlebitis and is usually treated with a warm compress applied several
- Continued bleeding can be a problem for people with
bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning
medicines can also make bleeding more likely. If you have bleeding or clotting
problems, or if you take blood-thinning medicines, tell your health
professional before your blood is drawn.