BNP
The hormone a stretched heart releases, measured in the blood to diagnose heart failure
B-type natriuretic peptide is a 32-amino-acid hormone released by heart muscle when it is stretched. Its blood level, or that of its partner fragment NT-proBNP, is a standard test for heart failure in breathless patients. As a medicine it was sold as nesiritide, now discontinued; as a test it has been FDA-authorized since 2000.
What is it?
Heart muscle cells release proBNP when they are stretched, and it splits into active BNP and the inactive fragment NT-proBNP, both measurable in blood. BNP acts on the natriuretic peptide receptor type A: it increases urine and salt output, widens vessels, and inhibits renin and aldosterone. Production rises sharply in heart failure.
Its value is diagnostic. In 1,586 breathless patients in emergency departments, BNP was more accurate than any history, examination or other test at identifying heart failure: 83.4% accurate at a 100 pg/mL cut-off, and a level under 50 made heart failure unlikely, with a negative predictive value of 96%. NT-proBNP did the same in later studies, with age-adjusted cut-offs of 450, 900 and 1,800 pg/mL.
It can also choose who to treat. In 300 people with type 2 diabetes, no heart disease and NT-proBNP above 125 pg/mL, stepping up blood-pressure and heart drugs cut cardiac hospitalisation or death by about two-thirds over two years.
Biosite's Triage BNP Test was authorised in November 2000. The recombinant drug form, nesiritide, has its own entry.
At a Glance
Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.
Published Research
These are the studies that describe BNP in practice, read from their PubMed abstracts: three emergency-department studies, a prevention trial and a review of its biology.
Breathing Not Properly
In 1,586 emergency patients with acute breathlessness, BNP was more accurate than any clinical finding: 83.4% accuracy at 100 pg/mL, and a negative predictive value of 96% below 50 pg/mL.
PRIDE
In 600 breathless emergency patients, NT-proBNP above 450 pg/mL (under 50) or 900 pg/mL (50 and over) diagnosed acute heart failure; under 300 pg/mL ruled it out with a negative predictive value of 99%.
ICON-RELOADED
In 1,461 breathless patients at 19 North American emergency departments, NT-proBNP diagnosed acute heart failure with an area under the curve of 0.91 using cut-offs of 450, 900 and 1,800 pg/mL by age.
PONTIAC
300 people with type 2 diabetes and NT-proBNP above 125 pg/mL but no heart disease were randomised; up-titrating RAS blockers and beta-blockers lowered cardiac hospitalisation or death (hazard ratio 0.351).
The biology behind the test
BNP is a 32-amino-acid hormone made mainly by ventricular muscle in response to stretch; NT-proBNP is the 76-amino-acid remainder; BNP acts on receptor type A to cause diuresis, vasodilation and lower renin and aldosterone.
Side Effects & Contraindications
Reported Side Effects
A blood test has no side effects; the hormone's drug form does.
Contraindications & Cautions
Interpretation limits rather than contraindications.
Legal Status
BNP tests are FDA-authorized devices; BNP itself is not a marketed drug.
Frequently Asked Questions
?What is BNP?
A 32-amino-acid hormone the heart releases when its muscle is stretched, measured in blood to diagnose heart failure.
?What is NT-proBNP?
The inactive fragment split off when BNP is made. It is measured the same way, with age-adjusted cut-offs.
?How accurate is the test?
In 1,586 breathless patients, BNP was 83.4% accurate at 100 pg/mL, and below 50 made heart failure unlikely.
?Is BNP a drug?
Its recombinant form was sold as nesiritide, now discontinued. BNP itself is used as a test.
References
- [pubmed] Maisel AS, et al. "Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure." N Engl J Med, 2002;347(3):161-7. PMID: 12124404.
- [pubmed] Januzzi JL Jr, et al. "The N-terminal Pro-BNP investigation of dyspnea in the emergency department (PRIDE) study." Am J Cardiol, 2005;95(8):948-54. PMID: 15820160.
- [pubmed] Januzzi JL Jr, et al. "N-Terminal Pro-B-Type Natriuretic Peptide in the Emergency Department: The ICON-RELOADED Study." J Am Coll Cardiol, 2018;71(11):1191-1200. PMID: 29544601.
- [pubmed] Huelsmann M, et al. "PONTIAC (NT-proBNP selected prevention of cardiac events in a population of diabetic patients without a history of cardiac disease): a prospective randomized controlled trial." J Am Coll Cardiol, 2013;62(15):1365-72. PMID: 23810874.
- [pubmed] Hall C. "Essential biochemistry and physiology of (NT-pro)BNP." Eur J Heart Fail, 2004;6(3):257-60. PMID: 14987573.
- [pubmed] Hobbs RE, et al. "Therapeutic potential of nesiritide (recombinant b-type natriuretic peptide) in the treatment of heart failure." Expert Opin Investig Drugs, 1999;8(7):1063-72. PMID: 15992106.
- [other] US FDA, device records (openFDA 510(k) and de novo): DEN000010, TRIAGE B-TYPE NATRIURETIC PEPTIDE (BNP) TEST, Biosite Incorporated, November 20, 2000. Read September 30, 2026.
Sources & Citations
Studies were read from PubMed; the test's authorization comes from openFDA device records, read September 30, 2026.
Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.