NT-pro-BNP (N-Terminal Pro B Type Natriuretic Peptide) Test

An NT pro-BNP test is performed along with a BNP test to detect heart failure and distinguish it from other causes of breathlessness, such as disorders of lungs (asthma, bronchitis and emphysema), kidneys or liver. The test is also used to monitor the treatment of heart failure and evaluate treatment success. Additionally, it helps assess the risk of heart failure in patients who have sustained a heart attack. Increased levels of NT pro-BNP in the blood after a heart attack indicate an increased risk of heart failure.

The test is usually carried out in medical emergencies when the symptoms are indicative of heart failure. Symptoms of heart failure include:

• Shortness of breath or severe breathlessness occurring after activity, at rest or at night, which disturbs sleep
• Swelling of feet, ankles and abdomen or all over the body
• Long-standing cough or wheezing. Coughing brings up white or pink-coloured mucus due to presence of blood (Read more: Coughing up blood causes)
• Frequent feeling of tiredness and weakness
• Loss of appetite with nausea
• Weakened memory and confusion due to a decrease in blood sodium content

You do not have to follow any special instructions or restrictions before the test. Fasting is not required before an NT pro-BNP test.

A nurse or laboratory technician will collect a blood sample from a vein in your arm and will store it in a white-top EDTA tube to prevent the blood from clotting. The results of the test are usually obtained in 15 minutes, which is helpful as the test is most often done in an emergency.

An NT pro-BNP test is not associated with severe side effects. Few complications that may occur include infection or bleeding at the site of needle prick, dizziness and haematoma. If you notice swelling, pain or redness at the site of needle insertion, please inform your doctor.

BNP and NT pro-BNP are secreted by the heart into the blood in similar quantities. However, the value of NT pro-BNP tends to remain high as it stays for a longer time in the blood before it is eliminated by the kidneys. 

Normal results: 

• BNP: < 100 pg/mL (picograms per millilitre)
• NT pro-BNP: < 400 pg/mL 

Normal results of BNP and NT pro-BNP indicate that the person is not suffering from heart failure.

Abnormal results: 

Higher than normal BNP and NT pro-BNP values indicate heart failure.

However, there are some other conditions where NT pro-BNP and BNP are raised, which include: 

• Disorders of the lungs (acute injury to lungs and pulmonary hypertension) 
• Kidney diseases (chronic kidney failure)
• Disorders of the liver (cirrhosis)
• High blood pressure
• Hypertrophy of heart

Certain factors resulting in abnormal values are:

• Age: Levels of NT pro-BNP are high in elderly people
• Kidney failure increases the level of NT pro-BNP irrespective of the presence of heart failure
• Gender: NT pro-BNP is higher in women compared to men
• Obesity is associated with falsely decreased levels of NT pro-BNP

A doctor would make the diagnosis depending on the clinical history and medical condition of the individual

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.