BNP (B-type natriuretic peptide) Test

If a doctor suspects that a patient is showing symptoms of heart failure, he/she may suggest a BNP test. The symptoms of heart failure include:

• Breathing difficulties
• Shortness of breath
• Chest pain
• Tiredness and fatigue
• Swelling of the feet and ankles
• Swelling in the abdominal area

Apart from checking for heart failure, this test is also performed to determine the severity of heart failure and check the effectiveness of the medicines being given for heart failure.

Since elevated BNP is also associated with lung, kidney and liver diseases, a BNP test rules out the possibility of conditions associated with these organs too. 

You will not require any preparations before this test. However, you should inform your doctor if you are on any medications as some drugs may affect the results of this test.

In order to conduct the test, a blood sample is required. A lab technician will draw the required amount of sample from a vein in your arm by injecting a sterile needle. The sample will be collected in an appropriate container/tube and sent to a laboratory for analysis.

Some people feel temporary lightheadedness after the test or notice bruising on the injection site. Some possible problems and risks associated with taking a blood sample are: 

• Difficulty in obtaining the sample
• Excessive bleeding at the site from where the blood is drawn
• Haematoma (accumulation of blood under the skin)
• Infection at the site where the needle is inserted

However, these risks can easily be reduced if proper precautionary measures are taken. 

Normal results:

Normally BNP values remain higher in women than in men and they increase gradually with age. However, they may still stay within the normal reference range unless there is heart failure.

A doctor will interpret the results according to your age and gender.

The normal reference range for most individuals is: <100 picograms/millilitre (pg/mL)

This indicates that you do not have heart failure. If the cause of symptoms is being determined, then it will be concluded that the symptoms are occurring due to another condition and not heart failure. 

It is important to note that normal results may vary among different laboratories due to differences in the measurements and testing methods. Therefore, it is essential to discuss the results with the doctor in order to get an accurate interpretation. 

Abnormal results:

Results > 100 pg/mL indicate abnormal results. An increase in BNP level is indicative of heart failure. The higher the value, the more the severity of heart failure. 

However, a rise in the BNP level may also be seen in the presence of the following conditions:

• Kidney failure
• Pulmonary hypertension
• Sepsis (severe infection)
• Lung problems

The test may be repeated to monitor the effectiveness of the treatment being given. If BNP levels remain high despite the treatment, it indicates disease progression or resistance to treatment. 

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.