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B-Type Natriuretic Peptide

Item Value
Approval req'd? No
Available Stat? Yes
Test code BNP
Performed by Parnassus Chemistry
In House Availability Test available 24 hours per day 7 days per week
Method Membrane Immunofluorescence Assay
Container type Lavender top
Amount to Collect 1 mL blood
Sample type EDTA whole blood
Preferred volume 1 mL blood
Min. Volume 0.3 mL blood
Units pg/mL
Normal range
Age Male Female
< 45 < 25 pg/mL < 48 pg/mL
45-54 < 40 pg/mL < 73 pg/mL
55-64 < 73 pg/mL < 82 pg/mL
65-74 < 64 pg/mL < 96 pg/mL
> 74 < 79 pg/mL < 181 pg/mL
Synonyms BNP; brain type; ANF; ANH; Atrial Natriuretic factor; Atrial Natriuretic Hormone
Stability Room temperature or refrigerated 24 hours.
Turn around times STAT 1 hour, Routine 4 hours
Additional information BNP is released from the heart (mainly the left ventricle) in response to increased wall tension and has both diuretic and natriuretic effects. BNP testing appears most useful for helping to rule out congestive heart failure in patients presenting with acute dsypnea. In patients being evaluated for acute dyspnea, BNP levels > 100 pg/mL had a sensitivity of 90% and specificity of 73% in diagnosing congestive heart failure (CHF) (McCullough PA et al Circulation 2002 106(4):416-422). In patients with BNP levels < 50 pg/mL, the negative predictive value for CHF was 96% (Maisel AS N Engl J Med 2002 347(3):161-7).

BNP levels have been shown to correlate with both NYHA functional class and invasively measured hemodynamic parameters. Treatment with ACE inhibitors, diuretics, and nitrates has been shown to decrease BNP levels in parallel with improving clinical symptoms (Richards, AM et al. Trends Endocr. Metabol. 13(4): 151-155. 2002). In patients with acute coronary syndromes, increased BNP levels are associated with increased risk for death during the subsequent 10 months as well with increased risk for myocardial infarction or heart failure (NEJM 345:1014-1021, 2001). Although BNP is renally cleared, acute and chronic renal failure per se do not appear to increase serum BNP significantly.

WARNING: Although normal BNP levels indicate a low probability of CHF, they do not exclude the possibility of heart failure or other serious cardiovascular or pulmonary disorders. Increased BNP levels are also not specific for CHF and can occur in patients with other serious conditions including pulmonary embolism, pulmonary hypertension, or acute myocardial infarction. BNP testing is not a substitute for careful cardiopulmonary evaluation and should not be the sole criterion for determining whether to admit or discharge a patient with dyspnea or other cardiovascular or pulmonary symptoms. BNP testing is also not recommended for screening for LV dysfunction or left ventricular hypertrophy in the general population (JAMA 288:1252-1259, 2002).

Higher levels of BNP are seen in women and older individuals. Age and gender specific reference ranges are listed above (from assay manufacturer, Biosite). Sensitivity and Specificity for Diagnosis of CHF in Patients Presenting to ED with Dyspnea:

BNP level (pg/mL) > 50 > 80 > 100 > 125 > 150
Sensitivity (%) 97 93 90 87 85
Specificity (%) 62 74 76 79 83
PPV (%) 71 77 79 80 83

from Maisel AS, N Engl. J. Med. 2002 347(3):161-7
Medical Necessity? Yes. Click here for more information
LOINC code 42637-9
Last Updated 10/15/2014 1:53:15 PM
Entry Number 82
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