Heart and vessels
NT-proBNP
A substance the heart releases when it is under strain; used to rule out heart failure in people with symptoms such as shortness of breath.
Everything about this testWhat it measures
When the heart muscle is stretched or under strain, especially in the left ventricle, the heart makes the hormone pro-BNP. This is cut into two pieces: BNP, which helps lower blood pressure and pass salt and water in the urine, and NT-proBNP, which has no function but stays in the blood longer. The test measures the amount of NT-proBNP. The more strain on the heart, the higher the value.
- Heart failure (the heart pumps less well than needed): a normal value makes heart failure unlikely
- Strain on the heart from other causes, such as atrial fibrillation, a heart valve disorder or high blood pressure in the blood vessels of the lungs
High
A raised NT-proBNP may fit heart failure, especially with symptoms such as getting tired or short of breath quickly during exertion, shortness of breath when lying flat, or swollen ankles; the higher the value, the more severe the heart failure usually is. A slightly raised value also occurs without heart failure: the value rises with age and is higher with reduced kidney function, atrial fibrillation, a pulmonary embolism, severe lung disease or after heavy exertion. A raised value is therefore not a diagnosis. For people with symptoms, the Dutch GP guideline (NHG) uses a single cut-off of 125 pg/ml (about 15 pmol/l); above it, an ultrasound of the heart is needed to confirm or rule out heart failure.
Low
A normal or low NT-proBNP makes heart failure unlikely, especially if the heart tracing (ECG) and the physical examination are also normal; the cause of any symptoms then usually lies elsewhere, for example in the lungs. With severe obesity the value comes out lower, which makes it harder to rule out heart failure. A low value does not cause symptoms itself.
Preparation
- Do you take biotin (vitamin B8, often in hair and nail supplements)? Stop at least 2 days before the sample is taken, or 4 days for a high dose.
If your result is abnormal
With a raised value, the GP arranges an ultrasound of the heart according to the Dutch GP guideline (NHG) on heart failure, usually through a referral to the cardiologist, to confirm or rule out heart failure; kidney function, blood count, thyroid and glucose are often measured as well. With a normal value, the GP looks for another cause of the symptoms.
Reliability
According to the Dutch GP guideline (NHG) on heart failure, NT-proBNP is a test for people with symptoms that fit heart failure, together with the consultation, a physical examination and a heart tracing. The test is especially strong at ruling out heart failure: a value below the cut-off makes heart failure unlikely. A raised value is less certain, because age, kidney function and other heart and lung diseases also raise the value; that is why an ultrasound of the heart then follows. The test is not meant for detecting heart failure in people without symptoms.
Limitations
- The value rises with age; in people over 75, a slightly raised result is often not caused by heart failure.
- Reduced kidney function and atrial fibrillation raise the value; severe obesity lowers it.
- Medicines for heart failure, such as water pills and some blood pressure medicines, lower the value; a normal result in someone taking these medicines does not rule out heart failure.
- Results and units (pg/ml or pmol/l) differ between measurement methods; preferably compare results within the same laboratory.
How common is this
In 2024, an estimated 256,400 people in the Netherlands had a diagnosis of heart failure; in 2023, about 8,000 people died of heart failure. Heart failure mainly occurs in older people.
Who is this useful for
Useful with symptoms that may fit heart failure: getting tired or out of breath quickly during exertion, shortness of breath when lying flat, swollen feet or ankles, or weight gain from fluid retention. In that situation the test is part of an examination by the GP, together with a physical examination and a heart tracing. Not meant for people without symptoms: small increases also occur in healthy people, so an abnormal result is then often not due to heart failure. Anyone who is suddenly severely short of breath or has chest pain should not wait for a blood test but contact the GP or 112 straight away.
Downsides and risks
- In people without symptoms, especially older people, a slightly raised value often leads to unnecessary worry and further tests without heart failure turning out to be present.
- A normal result can give false reassurance if the symptoms persist or get worse, or if someone already takes medicines that lower the value.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results