Brain Natriuretic Peptide (BNP) Test
At a Glance
Why Get Tested?
To diagnose the presence and severity of heart failure
When to Get Tested?
If you have symptoms of heart failure, such as breathlessness and fatigue, or if you are being treated for heart failure
Sample Required?
A blood sample taken from a vein in your arm
The Test Sample
What is being tested?
This test measures the concentration of BNP or NTproBNP in the blood. NTproBNP is an inactive fragment produced at the same time as BNP. BNP is a hormone that helps to regulate blood volume and therefore the work that the heart must do to pump blood around the body. Both BNP and NT proBNP are mainly produced by the heart's left ventricle (the organ's main pumping chamber). The heart releases more BNP and NTproBNP when the left ventricle is stretched from having to work harder as can happen in heart failure (when your heart is not strong enough to pump enough oxygen-rich blood and nutrients to meet your body's needs). BNP and NTproBNP levels increase in heart failure as well as in other diseases that affect the heart and circulatory system.
How is the sample collected for testing?
Blood is taken by needle from a vein in your arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
The Test
How is it used?
This test helps to diagnose and assess the severity of heart failure. Many UK hospitals and GPs do not yet use this test because it is new, relatively expensive and not incorporated into the local diagnostic and treatment pathway for patients with heart failure.
There are various causes of heart failure. Currently, the condition is diagnosed by physical symptoms such as difficulty breathing, breathlessness, and fatigue, in addition to chest X-rays and an ultrasound test called echocardiography. These diagnostic methods can still mistake heart failure for other conditions. BNP or NTproBNP measurementa can help doctors tell the difference between heart failure and other problems, such as lung disease. An accurate diagnosis is important because heart failure can be successfully treated, yet it is often under diagnosed and undertreated.
When is it requested?
A BNP test may be requested under the following circumstances:
- In your doctor's surgery, if you have symptoms that could be due to heart failure.
- In A&E, if your doctors need to quickly determine whether you are suffering from heart failure or some other medical problem.
What does the test result mean?
Elevated concentrations of BNP suggest that a person has heart failure, and the level of BNP or NTproBNP in the blood is related to the severity of the heart failure. Higher levels of BNP or NTproBNP also may be associated with a worse outlook for the patient.
Is there anything else I should know?
BNP is also used as a drug (nesiritide) designed to treat heart failure patients. If you are already on this treatment, measurement of BNP may be affected.
BNP and NTproBNP provide the same information for your doctor but the laboratory reported results for the different tests cannot be compared directly.
Common Questions
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Article Sources
NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
