This article talks about BNP (a protein released by the heart during heart failure and other cardiac problems) and also about the significance of BNP in the treatment of heart conditions.
BNP (brain natriuretic peptide) is a type of protein that is produced in the heart muscles, initially as pro-BNP. It belongs to a class of hormones known as natriuretic peptides.
These groups of hormones are divided into four, namely ANP, BNP, CNP, and DNP. Each of them is produced in different areas of the circulatory system.
ANP (Atrial Natriuretic Peptide): It is produced by the cardiac muscle cells in the heart's upper chambers (atria).
BNP (Brain Natriuretic Peptide): These are made by the cardiac muscle cells in the heart's lower chambers (ventricles).
CNP (C-Type Natriuretic Peptide): The endothelium of the blood vessels produces this protein.
DNP: It is found in the blood plasma but is thought to originate in the heart itself.
In instances of heart failure, two types of proteins are made by the heart. These include B-type natriuretic peptide (BNP) and N-terminal-pro BNP. Levels of both these proteins are measured in the BNP test. It holds the significance of determining the occurrence of heart failure in most cases. The levels of these proteins are increased during the event of heart failure and decrease with recovery.
1. When there is a suspicion of heart failure due to symptoms such as difficulty breathing and swelling or fluid build-up in the extremities, your doctor might advise you to check your BNP levels.
2. To know the severity of heart failure in patients diagnosed with congestive heart failure.
3. To check for kidney (renal) failure.
4. To check the effectiveness of treatment in a patient treated for heart failure.
The following symptoms indicate the need for a BNP test:
Irregular heart rate.
Difficulty in breathing.
Unexplainable weight gain.
Persistent cough with phlegm production.
BNP and NT-proBNP are measured using a simple blood test to help diagnose and monitor heart failure. BNP and NT-pro-BNP test results have different values.
Abstain from eating food for 7 to 12 hours before having a BNP test. However, drinking water is not a concern.
Inform your doctor about the medications you are taking as it is recommended to stop taking some medications prior to the test. This is because there may be interference with the results.
The test usually takes about 15 to 20 minutes.
Blood is drawn from the veins in the arms by a process called venipuncture. A hypodermic needle helps in this process.
A machine is then employed, over which the drawn blood is placed, to measure the BNP and NT-pro-BNP levels.
Since it involves drawing blood, patients in whom the sight of blood can bring about fainting or those who are weak, it is always advisable to have someone accompany the patient to the test as they find driving by themselves or traveling difficult.
It is rather a simple test and does not need much preparation. The stress level has a transient impact on your BNP values. Therefore it is recommended not to stress yourself about the test.
In general, the normal BNP values of women are a bit higher than those of men. BNP values usually increase with age, but they may stay within the normal range unless heart failure is present.
The below table depicts the values of BNP:
The following tables describe the normal value of NT-pro-BNP for age:
Note: The normal range varies from one lab to another, and your lab may have a different range for what is normal. Your lab report should contain the range your lab uses. Your doctor will evaluate your results based on your age and gender.
From the reports, your doctor can tell you if:
There is an increased amount of fluid or high pressure inside the heart.
There is severe heart failure.
There is a higher chance of sudden cardiac death in patients diagnosed with heart failure.
There are early signs of heart failure in people with kidney failure or insufficiency.
Overall, the result will be determined to be positive or negative by your doctor based on the reason the test was ordered.
BNP level is decreased in:
People who are obese.
Patients undergoing treatments with medications such as ACE inhibitors, diuretics such as Spironolactone, and beta-blockers.
It is increased in:
Females, more commonly.
Lung diseases like emphysema.
High blood pressure patients.
An overactive thyroid, like in a case of hyperthyroidism.
Very high cortisol levels.
Patients with kidney failure.
Advanced liver disease or end-stage liver disease.
Certain rare tumors.
The BNP test is very accurate in detecting heart failure. Accuracy is around 98 %. However, factors like stress and exercise may cause a temporary rise in BNP values.
As it is not a complex procedure, it does not bring about serious complications. However, since drawing blood is involved, there may be associated symptoms of venipuncture like:
Bleeding from the venipuncture site.
Soreness and formation of bruises at the site of puncture.
Since this might bring about lightheadedness, the patient is not advised to drive by themself. Other than this, all the above symptoms are transient and do not bring about serious health concerns.
In addition to the BNP test, the below tests help diagnose heart failure:
Complete blood count.
X-ray of the chest.
MRI (magnetic resonance imaging) of the chest.
BNP test is a blood test that is a useful means of diagnosing heart failure. Incidences of heart attacks can also be detected in this test. Being a relatively simple blood test, not much preparation is required. If you have been proposed to have a BNP test, it is always advisable to bring an attender with you. The values differ for different laboratories; therefore, to get it interpreted correctly, seeking the help of a physician is a must.
Last reviewed at:
28 Apr 2022 - 5 min read
Query: Hi doctor,I am a 46 year old male. My height is 184 cm and weight is 98 kg. I have been having balancing problems for over a year. It is some form of sensory ataxia. I also have compression in C4-C5 and C5-C6 cervical spine. I also have severe sleep apnea. I had some breathlessness and chest discom... Read Full »
Query: Hi doctor, I am a cardiac patient since 16 years after a massive MI followed by an angioplasty. Thereafter, I was taking medication to control high BP along with Aspirin as well as for cholesterol. Recently, I have another mild attack and did my second angioplasty. My BP is fluctuating between 150/9... Read Full »
Query: Hello doctor, I had a question about the ketone diet. I honestly do not understand the benefits of a ketone diet, what are they? Is a ketone diet good for those who are diabetic? Read Full »
Most Popular Articles
Do you have a question on Blood Tests or Cardiac Marker?Ask a Doctor Online