This test helps to diagnose and grade the severity of heart failure. Many hospitals and GP practices do not yet use this test because it is new and still being evaluated.

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. But these methods can still mistake heart failure for other conditions. BNP levels can help doctors to 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 traditionally underdiagnosed and undertreated.

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
• To monitor the effects of therapy for heart failure.

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

NOTE: A standard reference range is not usually available on this site for tests. Because reference values are dependent on many factors, including patient age, gender, sample population, and test method, numeric test results have different meanings in different laboratories. Your laboratory report should include the specific reference range for your test. Lab Tests Online AU strongly recommends that you discuss your test results with your doctor. For more information on reference ranges, please read Reference ranges and what they mean.

BNP is also used as a drug (nesiritide) designed to treat heart failure patients. If you are already on this treatment, your test results may be affected.