BNP (Blood)

Does this test have other names?

B-type natriuretic peptide, brain natriuretic peptide

What is this test?

This test looks for the hormone BNP in your blood. BNP stands for brain or B-type natriuretic peptide. It's made inside the pumping chambers of your heart when pressure builds up from heart failure. The test is an important tool for doctors to diagnose heart failure quickly.

Heart failure happens when your heart is not pumping blood well. This causes cells inside your heart to release BNP. This opens up blood vessels in your body to take pressure off your heart. A BNP blood test correctly shows heart failure about 9 out of 10 times.

The BNP test can help your doctor diagnose heart failure, plan treatment, see how well the treatment is working, and figure out when it's safe for you to leave the hospital. The BNP test can show how serious your heart failure is now and how severe it will be in the future. A BNP test is quite accurate, and it only takes about 15 minutes to get the results.

Why do I need this test?

You may need this test if your healthcare provider thinks you could have heart failure.

The main symptom of heart failure is trouble breathing (dyspnea). If you go to your healthcare doctor's office or the emergency room with trouble breathing, your provider will want to know the cause as quickly as possible. Many conditions can cause trouble breathing, but if you also have a blood test that is positive for BNP, heart failure is likely causing your symptoms.

You may also need this test so that your doctor can see how well your heart failure therapy is working.

What other tests might I have along with this test?

You may have a blood test called atrial natriuretic peptide (ANP). ANP is a hormone similar to BNP, but a different part of your heart makes it. You may also have other blood tests, a chest X-ray, an electrocardiogram, or an echocardiogram, which is an ultrasound of the heart.

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

BNP is measured in picograms per milliliter (pg/mL) or nanograms per liter (ng/L). In general, the more serious your heart failure, the higher your levels of BNP will be. But test results vary by age, sex, and body mass index. Normal values tend to go up with age. They also tend to be higher in women and lower in men. Both men and women who are obese tend to have lower levels.

How is this test done?

The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. 

Does this test pose any risks?

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.

What might affect my test results?

Other things besides heart failure can cause your BNP to rise, including:

• Kidney failure or being on dialysis.

• Long-term, or chronic, heart failure.

• Nesiritide, a synthetic form of BNP used to treat heart failure.

How do I get ready for this test?

You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don’t need a prescription and any illegal drugs you may use.