Blood test
BNP Blood Test
A BNP blood test measures a hormone released when the heart is under strain, helping to diagnose or rule out heart failure.
Quick answer
BNP Blood Test: what it is and what the results mean
BNP (B-type natriuretic peptide) and its related form NT-proBNP are hormones released by the heart when its chambers are stretched or under pressure. A simple blood test measures their level.
- Why it is done: It is used to help diagnose heart failure in people with breathlessness or swelling, to decide who needs an urgent heart scan (echocardiogram) and specialist review, and sometimes to monitor known heart failure.
- Understanding results: A normal or low level makes heart failure unlikely, while a raised level suggests the heart is under strain and prompts an echocardiogram and specialist assessment.
What it is
BNP (B-type natriuretic peptide) and its related form NT-proBNP are hormones released by the heart when its chambers are stretched or under pressure. A simple blood test measures their level.
Why it is done
It is used to help diagnose heart failure in people with breathlessness or swelling, to decide who needs an urgent heart scan (echocardiogram) and specialist review, and sometimes to monitor known heart failure.
What to expect
It is an ordinary blood test taken from a vein in the arm. No special preparation is usually needed, and results are available from the laboratory within a day or two.
Understanding the results
A normal or low level makes heart failure unlikely, while a raised level suggests the heart is under strain and prompts an echocardiogram and specialist assessment. Levels can also rise for other reasons, so results are interpreted in context.
Good to know
Risks and limitations
It is a very safe blood test. Levels can be raised by other conditions (such as kidney problems or atrial fibrillation) and lowered by obesity, so it supports diagnosis rather than confirming it alone.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
BNP Blood Test: frequently asked questions
Does a raised BNP mean I definitely have heart failure?
Not on its own. A raised level means the heart may be under strain and you need an echocardiogram and specialist review. Other conditions can also raise BNP, so it is one part of the assessment.
What is the difference between BNP and NT-proBNP?
They are closely related molecules released together by the heart; laboratories measure one or the other. Both are used in the same way to help assess heart failure, just with different reference ranges.
Related tests
Other blood test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- British Cardiovascular Society / relevant professional body
Building patient-education content for tests or procedures?
We create clear, accurate, referenced medical explainers and decision aids for teams.