Finding the right tests…
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Finding the right tests…
Hormonal
When your heart has to work harder than normal to pump blood, it releases a hormone called B-type natriuretic peptide, and this test measures that hormone's related fragment, NT-proBNP, in your blood. Your doctor orders it when you have breathlessness, swelling in your legs, or unexplained fatigue and needs to know whether your heart is behind it. It's not a general heart check; it's aimed specifically at heart failure, where the heart muscle can't pump strongly enough or fill properly between beats. A result well within the normal range for your age makes heart failure an unlikely explanation for your symptoms, which is often as useful to your doctor as a high one.
This test measures NT-proBNP, a protein fragment released by heart muscle under strain, reported in picograms per millilitre. Your heart releases more of it the harder it has to work to pump blood, so the number tracks the degree of strain on your heart rather than any single disease. Because levels rise naturally with age and differ slightly between men and women, your doctor reads your result against a range suited to your age group rather than one fixed cutoff for everyone. No special preparation, such as fasting, is needed before the blood draw.
NT-proBNP is released from the same heart muscle cells as BNP itself — one is the active hormone, the other an inactive fragment released alongside it in larger amounts — and both rise together when the heart is under strain. This is why NT-proBNP, checked on its own, gives your doctor roughly the same information as checking BNP directly.
The main use is sorting out breathlessness. If you come in with shortness of breath, ankle swelling, or unexplained tiredness, this test helps your doctor work out how likely it is that your heart, rather than your lungs or another cause, is behind it. A clearly high result points toward heart failure, though your doctor still needs an echocardiogram or other imaging to confirm the diagnosis and see what's actually happening inside your heart.
NT-proBNP isn't specific to heart failure. Kidney disease, since the kidneys help clear it from the blood, atrial fibrillation, valve disease, and even normal ageing can all push the number up without heart failure being present, so your doctor weighs your result against your symptoms and history rather than reading it in isolation.
If you're already being treated for heart failure, your doctor may repeat this test over time to see whether the strain on your heart is easing.
Both come from the same protein made inside heart muscle cells under strain — BNP is the active hormone, NT-proBNP is an inactive fragment released alongside it. Labs generally run one or the other, not both, and either gives your doctor a similar read on how hard your heart is working.
Not on its own. A high NT-proBNP makes heart failure more likely, but conditions like kidney disease, atrial fibrillation, and valve disease can raise it too, so your doctor confirms the diagnosis with an echocardiogram or other imaging.
A result well within the normal range for your age makes heart failure an unlikely explanation for your symptoms. Research on NT-proBNP has found levels below 300 pg/mL make heart failure very unlikely regardless of age, though your doctor will interpret your specific number.
This page is general information about the test, not medical advice. Your own report's reference ranges apply — please discuss your results with your doctor.
No. There's no special preparation, including fasting, needed before an NT-proBNP blood draw.
NT-proBNP rises gradually with age even in people with healthy hearts, so a level that would be concerning in a 40-year-old can be unremarkable in someone over 75. Your doctor reads your result against a range suited to your age group.
Yes. Your kidneys help clear NT-proBNP from your blood, so reduced kidney function can raise the level even without heart failure being present. Your doctor will usually check your kidney function alongside this test.
Yes, doctors also use it in people already diagnosed with heart failure to see whether treatment is easing the strain on the heart over time, alongside symptoms and other tests.