NT-proBNP — Normal Range & Interpretation
Full name: N-Terminal pro-B-type Natriuretic Peptide
NT-proBNP is the inactive N-terminal fragment released when proBNP cleaves into active BNP. The ventricular myocardium secretes it in response to wall stretch and volume overload, making it a cornerstone biomarker for diagnosing and prognosticating heart failure. Its longer half-life compared to BNP produces more stable serum levels, and clinicians use age-adjusted cutoffs of 450 pg/mL under 50, 900 pg/mL ages 50 to 75, and 1800 pg/mL over 75 to rule in acute heart failure.
| Male | Female | Unit | Category |
|---|---|---|---|
| <300 | <300 | pg/mL | Cardiac Markers |
Clinical Context
NT-proBNP is the inactive N-terminal fragment released when proBNP cleaves into active BNP. The ventricular myocardium secretes it in response to wall stretch and volume overload, making it a cornerstone biomarker for diagnosing and prognosticating heart failure. Its longer half-life compared to BNP produces more stable serum levels, and clinicians use age-adjusted cutoffs of 450 pg/mL under 50, 900 pg/mL ages 50 to 75, and 1800 pg/mL over 75 to rule in acute heart failure.
Elevations occur in systolic and diastolic heart failure, acute coronary syndrome, pulmonary embolism, pulmonary hypertension, atrial fibrillation, sepsis, and chronic kidney disease due to reduced renal clearance. Advanced age and female sex trend values higher at baseline. Obesity lowers NT-proBNP, which masks heart failure in patients with elevated BMI. Treatment with sacubitril-valsartan raises BNP but not NT-proBNP, making NT-proBNP the preferred monitoring marker on ARNI therapy.
FNPs see NT-proBNP on the boards most often in scenarios differentiating cardiac from pulmonary dyspnea in acute presentations. Expect questions linking elevated values to heart failure exacerbation, recognizing renal impairment as a confounder, and selecting NT-proBNP over BNP in patients prescribed sacubitril-valsartan. Know that values under 300 pg/mL effectively rule out acute heart failure.
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