Clinical Info
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Support a diagnosis of congestive heart failure (CHF)
B-type natriuretic peptide (BNP), also referred to as brain natriuretic peptide, is a member of a family of structurally similar peptide hormones that
includes atrial natriuretic peptide.1 BNP is a 32-amino-acid peptide that contains a 17-amino-acid ring structure that is formed as the result of an
internal disulfide bond. BNP is predominantly secreted by the ventricles of the heart in response to increased pressure. BNP acts as a vasodilator
and has diuretic and natriuretic properties. BNP suppresses both sympathetic tone and the renin-angiotensin system. These physiologic effects
serve to reduce intraventricular pressure and improve the symptoms of congestive heart failure (CHF).
BNP levels increase with age and can be transiently increased by vigorous exercise.1,2 BNP levels correlate with end-diastolic pressure and tend
to be increased in patients with diminished left ventricular ejection fraction.1,3 BNP levels have been shown to be useful in the diagnosis of patients
with symptoms that are consistent with CHF. Maisel and coworkers4 found that a BNP cutoff of 75 pg/mL could be used to predict systolic and/or
diastolic abnormalities accurately in symptomatic patients referred to echocardiology for left ventricular function studies. They found that this cutoff
identified patients with abnormal function from a population of 200 patients with a sensitivity of 95.9%, specificity of 86%, positive predictive value of
98%, and a negative predictive value of 89%. The overall accuracy of the diagnosis with a cutoff of 75 pg/mL was 93%. These results were similar to
those found by Dao and coworkers.5 They found that BNP levels could be used to accurately identify patients with CHF from a population of patients
presenting at the emergency room with shortness of breath (dyspnea). They found that a BNP value >80 pg/mL could be used to identify patients with
CHF from this population with a sensitivity of 97%, specificity of 98%, positive predictive value of 92%, and a negative predictive value of 98%.6
Footnotes
1. Maisel A. B-type natriuretic peptide levels: A potential novel “white count” for congestive heart failure. J Card Fail. 2001; 7(2):183-193. PubMed 11420771
2. McNairy M, Gardetto N, Clopton P, et al. Stability of B-type natriuretic peptide levels during exercise in patients with congestive heart failure: Implications
for outpatient monitoring with B-type natriuretic peptide. Am Heart J. 2002; 143(3):406-411. PubMed 11868044
3. Valli N, Georges A, Corcuff JB, et al. Assessment of brain natriuretic peptide in patients with suspected heart failure: Comparison with radionuclide
ventriculography data. Clin Chim Acta. 2001; 306(1-2):19-26. PubMed 11282090
4. Maisel AS, Koon J, Krishnaswamy P, et al. Utility of B-natriuretic peptide as a rapid, point-of-care test for screening patients undergoing echocardiography
to determine left ventricular dysfunction. Am Heart J. 2001; 141(3):367-374. PubMed 11231433
5. Dao Q, Krishnaswamy P, Kazanegra R, et al. Utility of B-type natriuretic peptide in the diagnosis of congestive heart failure in an urgent-care setting.
J Am Coll Cardiol. 2001; 37(2):379-385. PubMed 11216950
6. Wu AH, Packer M, Smith A et al. Analytical and clinical evaluation of the Bayer ADVIA Centaur Automated B-type natriuretic peptide assay in patients
with heart failure: A multisite study. Clin Chem. 2004 May; 50(5):867-873.
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Collection Instructions
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Container/Tube:: Lavender Top Tube
Specimen: 0.8 mL serum ( 0.5 mL min)
Transport Temperature: Frozen
Special Instructions
This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin
(also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test
about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.
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