What Is a Brain Natriuretic Peptide (BNP) Test?

Diagnosing heart failure is what a brain natriuretic peptide test (BNP) is used for — but a brain natriuretic peptide test may help prevent heart failure, too.

If you have symptoms of heart failure, your doctor will likely order a brain natriuretic peptide test. And that may sound confusing. After all, it’s your heart, not your brain, being tested, so you’ll likely ask: What is a brain natriuretic peptide (BNP) test?

Here’s the answer. Brain natriuretic peptide is a hormone secreted by cardiocytes — cells that comprise the heart muscle. A BNP test (which is performed with a simple blood sample) measures the amount of BNP in your blood.

If your heart is functioning normally, only a small amount of brain natriuretic hormone is typically found in your blood. If levels of BNP are high on a brain natriuretic peptide test, you may have heart failure or be at risk for the condition.

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What is a brain natriuretic peptide (BNP) test used for?

Heart failure is a chronic, progressive condition affecting close to 6 million Americans, according to the Centers for Disease Control and Prevention (CDC). A BNP test is an important part of the diagnosis, treatment, and possible prevention of the condition.

When you have heart failure, it doesn’t mean your heart will fail and stop beating — it means the heart muscle can’t pump enough blood to meet your body’s needs for blood and oxygen. Symptoms of heart failure include feeling short of breath during your daily activities and when lying down; weight gain due to swelling in your stomach, feet, legs and ankles; and often feeling weak and tired.

Depending on any symptoms and your medical history, your doctor may check you for heart failure during a medical appointment or as part of your yearly physical by ordering a brain natriuretic peptide test. If heart failure is suspected, you may also be given other blood tests, a chest x-ray, an electrocardiogram, or an echocardiogram (an ultrasound of the heart), according to the American Heart Association.

If you have urgent symptoms of heart failure, such as feeling very breathless, and go to an emergency room, a BNP test can be performed in about 15 minutes. A review of studies of these test results, published in the American Family Physician journal, concluded the test is a quick and inexpensive way to rule out heart failure — if a normal level of BNP is found.

Understanding a BNP test score

The normal values for the test vary from lab to lab and must be evaluated by your doctor based on other factors, including your health history and your gender. Test scores typically are higher in women than men and normally are elevated a bit with age. However, they stay within the normal range unless heart failure develops.

It’s important to note that while a negative test is highly accurate in ruling out heart failure, there are reasons why your test can be out of the normal range without heart failure. For example, lung disease — such as emphysema or chronic obstructive pulmonary disease (COPD) — can elevate BNP levels. And so can kidney disease, and kidney dialysis, or even a heart attack.

In addition to helping diagnose heart failure, the results of this test can show how serious your heart failure is and help your doctor plan treatment. By comparing the results of a baseline test with future BNP test results, your doctor can see how well treatments are working, too.

Can a brain natriuretic peptide test prevent heart failure?

Early diagnosis of heart failure, often thanks to the results of a BNP test, means treatment can start right away — improving both the quality and length of life of patients with heart failure. And now there’s evidence using these tests to spot very early changes in levels of brain natriuretic peptide might actually be able to halt the development of heart failure.

That’s the conclusion of updated guidelines on heart failure prevention, published by American College of Cardiology, American Heart Association, and the Heart Failure Society of America. By using the test, along with a physical exam and other tests to identify who is at risk for heart failure, doctors may be able to guide early treatments to prevent heart failure symptoms from developing.

“Preventing the progression to symptomatic heart failure is incredibly important,” said cardiologist Clyde Yancy, MD, chair of the guideline’s writing committee and chief of cardiology at Northwestern University Feinberg school of medicine in Evanston, Ill. “For the first time, we really believe the data are in hand to inform how we might best prevent this disease.”

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