BNP: A Blood Test That Can Detect Heart Failure
Learn how this quick test is used to diagnose and monitor heart failure.
Blood tests can explain a lot about your health. To find or monitor heart failure, your doctor may check the level of BNP, or b-type natriuretic peptide, in your blood.
BNP is a protein that your heart makes in response to heart failure. A simple blood test measures how much of this protein you have.
- High levels of BNP can show that you have heart failure or that it's getting worse.
- Lower levels of BNP may mean that heart failure is stable or that heart failure is not the right diagnosis.
- Sometimes this test is used in emergency settings to determine whether a person's breathing problems are caused by heart failure or another problem, such as lung disease.
A BNP test is fast and inexpensive. It's now used more often to monitor how heart failure is progressing. But experts say that more studies are needed to prove how effective a BNP test is for guiding treatment.
BNP and your heart
Your heart secretes BNP to maintain blood pressure and to keep your body from holding on to extra salt (sodium) and water. BNP relaxes blood vessels and helps your body move sodium to your kidneys and out into your urine.
In heart failure, the heart has to work harder to pump blood, or it may have problems filling normally with blood. This can cause fluid to build up in the lungs and other parts of the body.
High levels of BNP show that your body is releasing more of the protein to ease this strain on your heart.