B-type natriuretic peptide (BNP) is a hormone produced primarily by the heart’s ventricles. The heart releases BNP into the bloodstream when its muscle cells stretch or are under increased stress. Measuring BNP levels through a blood test offers insight into the heart’s current state and helps healthcare providers assess cardiac function.
Interpreting BNP Levels
A BNP test determines the concentration of this hormone. For most healthy adults, a BNP level below 100 picograms per milliliter (pg/mL) is considered normal. Levels exceeding this threshold suggest the heart is experiencing stress or dysfunction.
A “dangerously high” BNP level is a clinical interpretation, not a single fixed number. A level above 400 pg/mL often suggests acute heart failure. Values for acute heart failure can range from 450 pg/mL to over 1,800 pg/mL, influenced by age. Age, sex, and other health conditions can influence BNP results, with older individuals and females sometimes having naturally higher baseline levels.
What High BNP Indicates
An elevated BNP level indicates the heart is working harder to pump blood throughout the body. This often points to heart failure, a condition where the heart cannot circulate enough blood to meet the body’s demands. Higher BNP values correlate with increased severity of heart failure, reflecting the extent of ventricular strain.
While heart failure is the most common cause of high BNP, other conditions can also lead to elevated levels. Impaired kidney function, for instance, can raise BNP because the kidneys clear the hormone from the body. Other factors like severe infections (sepsis), pulmonary embolism, pulmonary hypertension, and certain lung diseases can also contribute to increased BNP. Despite these other potential causes, heart failure remains the primary diagnostic consideration for medical professionals when BNP levels are high.
Responding to an Elevated BNP Result
A dangerously high BNP level necessitates prompt medical attention and thorough follow-up. Healthcare providers will conduct a comprehensive clinical evaluation, including a detailed review of symptoms such as shortness of breath, fatigue, and swelling. A physical examination will also be performed to gather more information about the patient’s condition.
Further diagnostic tests are important to understand the underlying cause and severity of the heart’s distress. These include an echocardiogram to assess the heart’s structure and pumping function, and an electrocardiogram (EKG) to check for electrical activity and signs of strain. A chest X-ray may also be ordered to look for fluid accumulation in the lungs.
Management of an elevated BNP level focuses on addressing the root cause, most commonly heart failure. This may involve prescribed medications such as diuretics to reduce fluid, ACE inhibitors or beta-blockers to improve heart function, and other therapies aimed at reducing the heart’s workload. Lifestyle adjustments, including dietary changes and monitored physical activity, may also be recommended. Ongoing monitoring of BNP levels and the patient’s overall health is an ongoing process to ensure effective management and prevent complications.