NTproBNPn

NT-proBNP, or N-terminal pro B-type natriuretic peptide, is a non-active fragment released into the blood when the heart is under stress. It is produced primarily by ventricular cardiomyocytes in response to stretch and increased wall tension, and it is commonly measured to assess cardiac function and fluid status.

The biomarker is measured in blood, typically as plasma or serum NT-proBNP. Levels are influenced by multiple factors, including age, renal function, body mass index, sex, and comorbid conditions such as atrial fibrillation or pulmonary disease. Assay methods and reference ranges vary by laboratory, so results are interpreted in the context of the specific test and patient characteristics. In general, higher NT-proBNP levels indicate a greater likelihood of heart failure and correlate with worse prognosis.

Clinical uses include aiding the diagnosis of heart failure in patients with dyspnea, helping to distinguish cardiac from non-cardiac causes of breathlessness, and guiding risk stratification in acute and chronic cardiac conditions. In guidelines, NT-proBNP thresholds are age- and assay-dependent; lower values can effectively rule out heart failure in some settings, while markedly elevated levels suggest a higher probability and may prompt further imaging and management. It is also used to monitor disease progression and response to therapy in heart failure.

Limitations include reduced specificity for heart failure in the presence of renal impairment or obesity, and elevations can occur in other conditions such as pulmonary embolism, sepsis, and critical illness. NT-proBNP therefore should be interpreted with clinical context and imaging findings.