Full Form of NT-proBNP
NT-proBNP stands for N-terminal pro-B-type natriuretic peptide, which is a cardiac biomarker released in response to cardiac pressure or volume overload 1.
Biochemistry and Physiology
NT-proBNP is a fragment of the prohormone proBNP that is cleaved into:
- NT-proBNP (the inactive N-terminal fragment)
- BNP (the biologically active B-type natriuretic peptide)
Key Characteristics:
- NT-proBNP exists as a monomer in circulation 1
- It has a longer half-life (25-70 minutes) compared to BNP (13-20 minutes) 1, 2
- It is more stable in vitro than BNP, making it a preferred diagnostic marker in many clinical settings 2
Clearance Mechanism:
NT-proBNP is cleared passively by organs with high blood flow 1:
- 55-65% by the kidneys
- 20-25% by the liver
- 10-15% by musculoskeletal tissue
- 5-10% by the head and neck
Clinical Significance
NT-proBNP is elevated in conditions with:
- Pressure or volume overload
- Increased atrial or ventricular wall tension
- Salt and fluid overload 1
Common Conditions Associated with Elevated NT-proBNP:
- Acute or chronic heart failure (both systolic and diastolic)
- Valvular heart disease
- Left ventricular hypertrophy
- Atrial fibrillation
- Pulmonary embolism and severe pulmonary hypertension
- Acute or chronic renal failure
- Advanced liver cirrhosis with ascites
- Anemia
- Sepsis
- Certain endocrine disorders
- Severe neurological diseases 1
Interpretation Considerations
Several factors affect NT-proBNP levels and should be considered when interpreting results:
- Age (levels increase with age)
- Sex (women have higher levels than men)
- Renal function (levels increase with declining kidney function)
- Body mass index (obesity results in lower levels) 2
For patients with reduced kidney function (GFR <60 mL/min/1.73m²), higher diagnostic thresholds are recommended as NT-proBNP levels may be artificially elevated due to reduced renal clearance 2.
Clinical Application
NT-proBNP is valuable for:
- Diagnosis of heart failure
- Assessment of heart failure severity
- Monitoring treatment response
- Prognostication in heart failure patients 2, 3
A decrease in NT-proBNP levels following treatment is associated with clinical improvement, making it a useful marker for monitoring therapy effectiveness 4.