What is an NT-proBNP test?
This test measures the level of NT-proBNP (N-terminal pro-B-type natriuretic peptide) in a sample of your blood. NT-proBNP is a substance released mainly by the heart when the heart muscle is under increased pressure or is working harder than normal.
When the heart chambers are stretched or under stress, the heart produces a hormone called BNP. At the same time, an inactive fragment called NT-proBNP is released into the blood. NT-proBNP does not directly affect the heart, but it remains in the blood longer than BNP, making it useful for laboratory testing.
An NT-proBNP test can provide important information to help detect, diagnose, assess, and monitor heart failure and other conditions that affect how well the heart is working.
Other names: NT-proBNP, N-terminal pro-B-type natriuretic peptide, N-terminal pro-BNP
What is it used for?
An NT-proBNP test may be used to help:
Diagnose heart failure
Heart failure occurs when the heart cannot pump blood as effectively as the body needs. When the heart is under increased pressure or strain, NT-proBNP levels often increase.
The test can help determine whether symptoms such as:
Shortness of breath
Difficulty breathing when lying down
Swelling of the legs, ankles, or feet
Fatigue or weakness
Rapid or irregular heartbeat
may be related to heart failure.
Assess the severity of heart failure
NT-proBNP levels may provide information about how much stress the heart is under. Higher levels can be associated with more severe heart failure, although results must always be interpreted together with symptoms and other clinical findings.
Monitor heart failure treatment
NT-proBNP testing may be used to monitor patients who have been diagnosed with heart failure. Changes in NT-proBNP levels can provide information about how the heart is responding to treatment.
Help distinguish heart failure from other causes of breathing problems
Shortness of breath can have many causes, including lung disease. NT-proBNP testing may help healthcare providers determine whether heart failure is contributing to the symptoms.
Why do I need an NT-proBNP test?
You may need an NT-proBNP test if:
You have symptoms that may suggest heart failure, such as shortness of breath or swelling of the legs.
Your healthcare provider wants to determine the cause of unexplained breathing difficulties.
You have already been diagnosed with heart failure and your provider wants to monitor your condition.
Your provider wants to assess the severity of your heart failure.
You have other conditions that may put stress on your heart and require an assessment of cardiac function.
What happens during an NT-proBNP test?
An NT-proBNP test usually uses a sample of your blood.
During a blood test, a healthcare professional will take a blood sample from a vein in your arm using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial.
You may feel a little sting when the needle goes in or out. The procedure usually takes less than five minutes.
Will I need to do anything to prepare for the test?
Usually, no special preparation or fasting is required for an NT-proBNP blood test.
However, follow any specific instructions given by your healthcare provider or laboratory.
Tell your healthcare provider about any medicines you are taking, because some medicines can affect NT-proBNP levels.
Are there any risks to the test?
There is very little risk to having a blood test.
You may have slight pain, bruising, or tenderness at the site where the needle was inserted. These symptoms usually go away quickly.
What do the results mean?
The meaning of your NT-proBNP result depends on several factors, including your age, symptoms, kidney function, other medical conditions, and the clinical situation.
In general:
A high level of NT-proBNP
A high NT-proBNP level may indicate that the heart is under increased stress or pressure. Conditions associated with increased NT-proBNP include:
Heart failure
Acute coronary syndrome or myocardial infarction
Heart valve disease
Cardiomyopathy
Abnormal heart rhythms, such as atrial fibrillation
Pulmonary hypertension
Pulmonary embolism
Kidney dysfunction or kidney failure
Other conditions that increase pressure or strain on the heart
NT-proBNP levels can also increase with increasing age, so age-specific interpretation may be important.
A low level of NT-proBNP
A low NT-proBNP level generally makes significant heart failure less likely, particularly in patients presenting with symptoms such as shortness of breath.
However, a low result does not completely rule out heart failure. NT-proBNP levels may be lower than expected in some people, particularly those with obesity.
Important note
NT-proBNP is not interpreted using a single universal cutoff for every patient. The appropriate reference or diagnostic cutoff can depend on the patient's age, clinical setting, and whether the test is being used for suspected acute heart failure or chronic heart failure.
Your healthcare provider will interpret the result together with your symptoms, physical examination, ECG, imaging tests such as echocardiography, and other laboratory results.
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