B-Type Natriuretic Peptide
B-type natriuretic peptide (BNP) is a hormone your heart releases when its chambers are stretched or under strain. A blood test measures how much is circulating.
BNP levels tend to rise when the heart is working harder than usual, which makes the test useful in evaluating and monitoring heart failure. It can help clinicians sort out whether symptoms like shortness of breath are related to the heart. It is generally used in a clinical context alongside an exam and other tests rather than as a routine screen.
A higher BNP often reflects increased strain on the heart and is commonly seen in heart failure, though levels can also rise with age, kidney disease, and other conditions. Because it is usually an acute or clinical-context test, it is interpreted with your symptoms, exam, and imaging. A single number is best understood in the setting it was ordered.
A low BNP is generally reassuring and makes significant heart strain from heart failure less likely as an explanation for symptoms. Low levels are the expected normal finding.
Lower values within the normal range are typical when the heart is not under strain. Your clinician will interpret your result based on your symptoms and overall health.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.