At a glance

Also known as

BNP; N terminal pro B type natriuretic peptide; NT-proBNP

Why get tested?

To exclude heart failure as a cause for shortness of breath (dyspnoea) or diagnose the presence and severity of heart failure.

When to get tested?

If there are symptoms of heart failure, such as shortness of breath and fatigue, or in persons being treated for heart failure.

Sample required?

A blood sample drawn from a vein in your arm

Frequency of testing is at your doctor's discretion or at intervals to monitor for heart failure.

Test preparation needed?
None

What is being tested?

 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 produced mainly in the heart’s left ventricle (the organ’s main pumping chamber). When the left ventricle is stretched, the concentrations of BNP and NT-proBNP in blood can increase markedly. This situation indicates that the heart is working harder  and having more trouble meeting the body's demands. This may occur in heart failure (when your heart is not strong enough to pump enough oxygen-rich blood and nutrients to meet your body's needs), as well as other diseases that affect the heart and circulatory system.

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

How is it used?

Brain natriuretic peptide (either BNP or NT-proBNP) may be used to help diagnose heart failure and to grade the severity of that heart failure. There are various causes of heart failure. Currently, the condition is diagnosed by the presence of symptoms such as swelling in the legs (oedema), difficulty breathing, shortness of breath, and fatigue, in addition to chest X-rays and an ultrasound test called echocardiography. However, heart failure is still often confused with other conditions. BNP and NT-proBNP levels can help doctors differentiate between heart failure and other problems, such as lung disease. An accurate diagnosis is important because heart failure can be successfully managed with various medical treatments.

When is it requested?

A brain natriuretic peptide test may be ordered under these circumstances:

  • In your doctor's office, if you have symptoms that could be due to heart failure. These may include:
           - difficulty breathing, shortness of breath
           - fatigue
           - swelling in the feet, ankles, legs, abdomen.
  • In the emergency room, if you are in crisis and doctors need to quickly determine whether you are suffering from heart failure or some other medical problem.
  • To monitor the effects of therapy for heart failure.

What does the test result mean?

A normal result for either BNP or NT-proBNP would exclude the presence of heart failure with a high degree of confidence, indicating the person's symptoms are due to a different condition.

Higher-than-normal results suggest that a person is in heart failure, and the level of BNP or NT-proBNP in the blood is related to the severity of heart failure. Higher levels of BNP or NT-proBNP also may be associated with a worse outlook (prognosis) for the patient.
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.

About Reference Intervals

Is there anything else I should know?

BNP and NT-proBNP levels decrease in most patients who have been taking drug therapies for heart failure, such as ACE inhibitors, beta blockers, and diuretics. 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.
Levels of both BNP and NT-proBNP tend to increase with age. Levels of NT-proBNP and BNP are increased in persons with kidney disease.

While both BNP and NT-proBNP will rise with left ventricle dysfunction and either can be measured, they are not interchangeable and the results cannot be directly compared.

Common Questions

How common is heart failure?

Heart failure is very common in the elderly and affects about 1.5 to 2% of the Australian population.

How is heart failure treated?

For information on treatment, please visit the National Heart Foundation web site.

Last Review Date: June 14, 2019