B-type Natriuretic Peptide (BNP)

Heart failure is also called congestive heart failure. If you have this condition, your heart has trouble pumping enough oxygen-rich blood to meet your body's needs.

Brain natriuretic peptide (BNP) is a protein that's a type of hormone. A hormone is a chemical messenger in your bloodstream that controls the actions of certain cells or organs. BNP has "brain" in its name because that's where researchers first discovered it. Your heart makes and releases BNP into your bloodstream when it's working harder than normal to pump blood. Two types of natriuretic peptides can be measured to check for possible heart failure, and your health care provider will decide which to test.

The meaning of your test results will depend on your age, sex, medical history, family history, and the results of other tests. Ask your provider to explain what the results of your BNP or NT-proBNP test say about your health and how this information may affect your treatment.

Higher than normal levels of BNP or NT-proBNP mean that you could have heart failure. In general, the higher the level, the more serious heart failure may be. As a rough guide for adults with new shortness of breath, a BNP under about 100 pg/mL (or NT-proBNP under about 300 pg/mL) makes acute heart failure less likely, while clearly higher values strongly suggest it. The 'in-between' range often needs more testing. Cutoffs are higher in older adults and in people with kidney disease or atrial fibrillation, so your provider will interpret your number in context.

BNP can also be raised by other heart-related conditions, such as a recent heart attack, thickening of the heart muscle (left ventricular hypertrophy), recovery after a procedure to open blocked arteries, and high blood pressure. Other conditions, including kidney failure, heart valve disease, and certain lung conditions such as pulmonary embolism, can also raise BNP.

Normal results on a BNP or NT-proBNP usually mean that you're unlikely to have heart failure. Your provider may order other tests to find out what's causing your symptoms. Falling BNP levels over time can also be a sign that treatment for high blood pressure or heart failure is working.

If you have obesity, your weight may affect the accuracy of your test results, making your levels lower than they really are. If your provider suspects heart failure, you may have other heart health tests even if your BNP or NT-proBNP levels are normal.