BNP and NT-proBNP: what they are, what they tell you and when they’re tested

BNP and NT-proBNP are two pieces of the same hormone. The heart releases them into the blood when its walls stretch under too much pressure or fluid. The higher they are, the more the heart is under strain. A doctor reads them, together with your symptoms and a heart scan. If you have sudden breathlessness or chest pain, call 112.

When they’re tested

Doctors mostly order them when you are breathless, tired or have swollen ankles and they suspect heart failure. In the emergency department they help tell whether breathlessness comes from the heart or the lungs. They are also used to follow people who already have heart failure.

In some people at risk, for example with diabetes, high blood pressure or coronary disease, a doctor may order them without symptoms, to spot a heart that is struggling early.

They are not a routine test for people who feel well. That is why Rosa does not test them. Instead it looks at what strains the heart and arteries over the years: ApoB, LDL cholesterol, blood sugar, HbA1c and kidney function.

What they tell you, and what they do not

A low value makes heart failure very unlikely. That is their strength: they help rule it out.

A high value says the heart is under strain, but not why. It can be heart failure, atrial fibrillation, a diseased valve or a lung problem. A heart scan is needed to find out.

The higher they are, the more closely your doctor follows things: they also say how things are likely to go in the months after.

That is why they are read together with other tests:

Normal BNP and NT-proBNP levels

BNP and NT-proBNP cannot be compared with each other: for the same heart, NT-proBNP gives higher numbers. Your report says which one was measured.

Outside hospital, in people with symptoms, guidelines consider heart failure unlikely with a BNP below 35 pg/mL or an NT-proBNP below 125 pg/mL. In the emergency department, higher thresholds are used.

Values rise with age on their own, and many reports print a limit that changes with age. In people with a lot of extra weight they are lower, sometimes by half. That is why the value has to be read by a doctor.

If your BNP is high or low

What raises BNP and NT-proBNP

The first cause is the one doctors look for most. There is often more than one.

What can skew the result

A few things change them without any change in the heart.

When to worry

Talk to your doctor if:

Frequently asked questions

What are normal BNP levels? Outside hospital, in people with symptoms, heart failure is unlikely below 35 pg/mL. The limit on your report may differ and change with age.

NT-proBNP: what are normal levels by age? They rise with age, so many labs print different limits by age. Outside hospital, in people with symptoms, heart failure is unlikely below 125 pg/mL. The range on your report is what counts.

What is the difference between BNP and NT-proBNP? They are two pieces of the same hormone and tell the same story. NT-proBNP has higher numbers and stays in the blood longer. They cannot be compared with each other.

Is a high BNP always heart failure? No. Atrial fibrillation, diseased valves, lung problems, kidneys that work less well and age raise it too. Your doctor reads it with your symptoms and a heart scan.

Does Rosa test BNP? No. Rosa measures ApoB, LDL cholesterol, blood sugar, HbA1c and creatinine, which say a lot about what strains the heart over the years. If your doctor wants BNP or NT-proBNP, they order it separately.

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