- Atrial natriuretic peptide
- BNP
- Brain natriuretic peptide
- Pro-BNP
- Plastic lavender top tube
- 4 mL of venous blood
Additional information on specimen collection:
- Reject:
- Non-EDTA plasma specimen
- EDTA plasma collected in glass tubes
- Specimen that has undergone hemolysis
- Specimen should be frozen immediately and maintained frozen until tested.
- Specimen may need to be fasting. Check with your laboratory.
- This test measures the concentration of BNP in the blood
- BNP is a cardiac peptide neurohormone secreted primarily by the myocytes in the cardiac ventricles
- When the cardiac ventricles become stressed and as blood volume expansion or pressure overload occurs, the left ventricular myocytes secrete the precursor pro-BNP, which in turn releases the active hormone BNP
- BNP acts as a vasodilator, and has diuretic and natriuretic properties
Clinically, the BNP test is useful in:
- Confirming the diagnosis of heart failure
- Monitoring prognosis and therapy in patients with heart failure
- Evaluation of dyspnea to differentiate between heart failure and pulmonary disease, pneumonia, ARDS or other pulmonary disease being the primary etiology
- Screening for LV dysfunction
- As a marker of ventricular systolic and diastolic dysfunction
Additional information:
- BNP levels increase in proportion to severity of heart failure
- BNP is detectable even with minimal clinical symptoms
- BNP regulates blood pressure and fluid balance by counter-balancing the renin-angiotensin system
- Like atrial natriuretic peptide, BNP also increases the excretion of sodium and water by increasing the glomerular filtration and inhibiting renal sodium reabsorption
- BNP causes vasodilation by inhibiting the secretion of aldosterone and renin
- Women have slightly higher BNP levels than men
- BNP level increases with the age of the person
- A rising BNP level suggests a higher risk for adverse outcomes and suggests need for more aggressive therapy
- Studies have shown that BNP testing shortens the time to CHF diagnosis and reduces the costs
- BNP levels are significantly higher in heart failure patients with restrictive cardiomyopathy than in those with symptoms due to constrictive cardiomyopathy
- Renal failure patients often have chronically elevated levels of BNP; Comparison of baseline level to current level is useful in determining fluid overload states
- Drugs interfering with the test results, include:
- Cardiac glycosides
- Diuretics
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
| Conv. units (pg/mL (ng/L)) | SI units (pmol/L) | |
|---|---|---|
| Normal | 100 | 28.9 |
| Borderline (Heart failure might be present) | 100-300 | 29-87 |
Consult your laboratory for their normal ranges as these may vary somewhat from the ones listed below.
BNP >100 pg/mL (28.9 pmol/L) may be considered abnormal. Values >300 pg/mL (87 pmol/L) are most likely to represent heart failure.
Mean BNP concentration ± SD with increasing severity of congestive heart failure (CHF):
- NYHA Class I: 240 ± 290 pg/mL (ng/L)
- NYHA Class II: 390 ± 370 pg/mL (ng/L)
- NYHA Class III: 640 ± 450 pg/mL (ng/L)
- NYHA Class IV: 820 ± 440 pg/mL (ng/L)
- Ascites (Hepatic cirrhosis)
- Cardiac inflammation
- Cardiac allograft rejection
- Myocarditi
- Endocrine disorders
- Cushing's syndrome
- Primary hyperaldosteronism
- Heart failure
- Kawasaki's disease
- Left ventricular hypertrophy
- Myocardial infarction
- Old age
- Primary pulmonary hypertension
- Renal failure
- Ventricular dysfunction
- Battaglia M et al. Accuracy of B-type natriuretic peptide tests to exclude congestive heart failure: systematic review of test accuracy studies. Arch Intern Med. 2006 May 22;166(10):1073-80.
- Cardarelli R et al. B-type natriuretic peptide: a review of its diagnostic, prognostic, and therapeutic monitoring value in heart failure for primary care physicians. J Am Board Fam Pract. 2003 Jul-Aug;16(4):327-33.
- Hutcheon SD et al. B-type natriuretic peptide in the diagnosis of cardiac disease in elderly day hospital patients. Age Aging. 2002 Jul;31(4):295-301
- Jeffrey S. BASEL: BNP testing shortens time to CHF and reduces costs. Theheart.org from WebMD®. [Homepage on the Internet] Last updated on August 31, 2003. Last accessed on August 18, 2006. Available at URL: http://www.theheart.org/viewArticle.do?primaryKey=242297&from=/searchLayout.do
- Morrison LK, Harrison A, Krishnaswamy P, et al. Utility of a rapid B-natriuretic peptide assay in differentiating congestive heart failure from lung disease in patients presenting with dyspnea. J Am Coll Cardiol 2002 Jan 16; 39(2):202-9.
- Mueller C et al.Use of B-Type Natriuretic Peptide in the Evaluation and Management of Acute Dyspnea. NEJM. 2004;350:647-654.
- Peacock IV WF.The B-type natriuretic peptide assay: A rapid test for heart failure. Cleveland Clinic Journal of Medicine. 2002;3:243-51.
- Stiles S. BNP level may distinguish restrictive from constrictive cardiomyopathy. Theheart.org from WebMD®. [Homepage on the Internet] Last updated on June 6, 2005. Last accessed on August 18, 2006. Available at URL: http://www.theheart.org/article/498527.do