The heart is a crucial internal organ within the human body, pumping blood enriched with oxygen and nutrients to other cells, tissues at the rate of 60 – 100 beats per minute (bpm), in addition to transporting metabolic wastes for elimination from the system and maintaining normal blood pressure in the blood vessels of the arteries and veins. Hence, when any health anomalies arise in the cardiac tissues, they must be promptly diagnosed and treated, to ensure timely recovery and overall wellbeing. A key diagnostic assay that detects instances of heart failure is the brain natriuretic peptide test also referred to as the B-type natriuretic peptide test or the BNP test.

Also Read: Heart Failure: Symptoms, Causes, Types And Treatment

What Is The BNP Test?

The BNP test is a diagnostic analysis that measures the amount of BNP hormone in the blood. Two central hormones – BNP i.e. brain natriuretic peptide and ANP – atrial natriuretic peptide are responsible for keeping the arteries and veins widened or dilated. This facilitates the smooth flow of blood via the circulatory tubules and averts the formation of blood clots. Furthermore, the optimal hormonal activity of BNP and ANP ensure kidney wellness and aid in the elimination of salts and fluids from the body.

In a normal individual, the levels of BNP in the bloodstream are within the normal range. However, in cases of congestive heart failure, the functioning of the heart is hampered and it fails to pump blood across the entire body since the walls of the heart chambers – the ventricles, become very weak and fragile. As a result, the pressure within the heart vessels, as well as the systemic fluid volumes, increase and more BNP is produced to balance blood pressure and bodily fluid levels. This rise above the normal range of BNP is detected in the BNP test and helps identify an instance of heart failure.
Brain Natriuretic Peptide BNP Test

Why It Is Done:

The chief purpose of the BNP test is to detect heart failures as soon as any typical symptoms arise in the patient such as chest pain/angina or breathing difficulty. A timely diagnosis and pertinent medical treatment for heart failures prevent grave complications and safeguard the cardiac tissues from further damage. The physician also suggests the patient undergo a BNP test for the following symptoms:

  • Constant fatigue and body weakness with no underlying ailments
  • Sudden unexplained weight gain
  • Trouble with memory, concentration and lowered brain functions
  • Frequent coughing with discomfort in the chest
  • Irregular heartbeats/heart rate i.e. arrhythmia
  • Shortness of breath with gasping
  • Loss of appetite with nausea, vomiting

Moreover, a BNP test is a preliminary assay to identify if the patient has heart failure. If subsequent advanced tests do not confirm cardiac issues, then higher than normal BNP levels could also be due to lung problems, kidney malfunctioning or obesity.

Also Read: Obesity: Causes, Symptoms And Treatment


The patient does not need to follow any specific diet restrictions prior to the BNP test. The assay is performed by a doctor or trained nurse in a clinic or hospital setting. The BP test is carried out by collecting a blood sample from the patient, drawn from a vein in the arm utilising a hypodermic needle i.e. a sterilized pricking apparatus that infiltrates the region beneath the top-most layer of the skin – the outermost dermal tissues. This protocol is termed venipuncture, as it involves poking a vein to extract a blood sample from the patient. The blood that is collected is then processed through a machine that calculates the amount of BNP in the sample.


There are no major risks associated with the BNP test. It involves a fundamental process of drawing blood from a vein in the arm of the patient. At times, the patient may experience slight pain, redness, discomfort at the site of injection of the hypodermic needle after the BNP test, which generally subsides within a day or two.

Nevertheless, if the patient is already feeling very exhausted or encounters fear at the sight of blood or an aversion to needles, then it is advised for a family member or close friend to accompany them for the BNP test to ensure to get them back home safely in case they develop dizziness or fainting episodes.


The results of the BNP test are usually available within 15 – 30 minutes following the procedure. However, in case the blood sample of the patient needs to be analysed in another advanced diagnostic laboratory facility, then the results may be processed only after a few days to one week post the test.

The results of the BNP test, otherwise called the B-type natriuretic peptide test or the brain natriuretic peptide test are as follows:

Normal: less than 100 pg/mL of BNP

High: more than 400 pg/mL of BNP

High numbers imply an increased possibility of congestive heart failure and the medical expert conducts additional tests of electrocardiogram (ECG), chest X-ray and cardiac MRI to confirm the instance of heart failure.

Intermediate: values between 100 pg/mL to 400 pg/ml could still indicate heart trouble and the healthcare provider conducts more analytical studies to confirm the same.

The values of BNP are measured in picograms per millilitre i.e. pg/mL.

Though the levels of BNP do become higher with age and are relatively greater in women than in men, the values also depend on the person’s body mass index (BMI) and medical history. Elevated BNP levels are witnessed in overweight and obese people, besides in individuals with underlying chronic health conditions like diabetes, hypertension, owing to excess pressure on the heart. Following the medications and lifestyle tips advised by the doctor help to bring down BNP levels and ensure heart health.