B-Type Natriuretic Peptide (BNP) Test
If you have symptoms of heart failure such as breathlessness, fatigue and/or swelling (oedema) of the legs
A blood sample taken from a vein in your arm
This test measures the concentration of BNP or NT-proBNP in the blood. BNP is a hormone that helps to regulate blood volume. NT-proBNP is an inactive fragment produced at the same time as BNP. 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 NT-proBNP 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 NT-proBNP concentrations 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.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
How is it used?
There are various causes of heart failure and the condition can be of chronic (long term) or acute (sudden) onset. The condition is usually suspected based on physical symptoms such as difficulty breathing, breathlessness, fatigue or swelling (oedema) in the legs. If the diagnosis is unclear, BNP or NT-proBNP measurements 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.
In the UK, healthcare professionals use BNP (or NT-proBNP) to exclude the presence of chronic heart failure. A normal BNP result in an untreated patient makes a diagnosis of heart failure unlikely. An elevated BNP concentration requires further investigation; your healthcare professional should arrange for you to see a specialist and to have an echocardiogram (ECG) , which will confirm whether heart failure is present. By performing a BNP test first not all patients, in whom heart failure is suspected, have to be referred for further testing in a hospital. The BNP result (e.g. how high it is), is also used to determine how quickly you should be seen by a specialist.
A 2014 guideline produced by the National Institute of Health and Care Excellence (NICE) also promotes the use of BNP (or NT-proBNP) in the initial assessment of a patient presenting with new suspected acute heart failure (heart failure of sudden onset / deterioration). A normal BNP result is used to rule out the diagnosis, whereas a raised BNP concentration should be followed up with an ECG to confirm the diagnosis.
The role of BNP in heart failure prognosis and monitoring is unclear. Therefore the test is not routinely used for these purposes in the UK.
When is it requested?
What does the test result mean?
A normal BNP result implies the patient does not have heart failure and the symptoms are due to a different condition. Elevated concentrations of BNP suggest that a person has heart failure, but further tests are required before the diagnosis is made. In general, the concentration of BNP increases as heart failure develops / deteriorates and decreases when the condition is stabilised.
Is there anything else I should know?
Drugs such as ACE inhibitors, beta-blockers and diuretics can decrease BNP and NT-proBNP concentrations. It is important to inform your healthcare professional if you are taking these medications, so the test result can be interpreted correctly. Do not stop taking these medications without consulting with your healthcare professional.
BNP and NT-proBNP results provide the same information for your doctor but results for the different tests cannot be compared directly, and measurements should not be interchanged.
How common is heart failure?
Heart failure is very common in the elderly and affects about 1 in 100 people in the UK.
How is heart failure treated?
There are many treatments available and treatment will be tailored to the individual. For information on treatment, please visit the British Heart Foundation web site.
Release of BNP or NT-proBNP is a natural response to heart failure. As your heart failure is treated, the levels of BNP or NT-proBNP may decrease.
On This Site
Tests: Cardiac Biomarkers
Conditions: Heart failure
Elsewhere On The Web
British Heart Foundation
NICE guideline CG108 (Chronic Heart failure in Adults: Management)
NICE guideline CG187 (Acute heart failure: Diagnosis and Management)