Mobile Site ›
Print Friendly View

Test ID: PBNP    
NT-Pro B-Type Natriuretic Peptide (BNP), Serum

‹ Back to Hematology index

Useful For Suggests clinical disorders or settings where the test may be helpful

An aid in the diagnosis of congestive heart failure

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

B-type natriuretic peptide (brain natriuretic peptide: BNP) is a small, ringed peptide secreted by the heart to regulate blood pressure and fluid balance.(1) This peptide is stored in and secreted predominantly from membrane granules in the heart ventricles in a pro form (proBNP). Once released from the heart in response to ventricle volume expansion and/or pressure overload, the N-terminal (NT) piece of 76 amino acids (NT-proBNP) is rapidly cleaved by the enzymes corin and/or furin to release the active 32 amino acid peptide (BNP).(2)

 

Both BNP and NT-proBNP are markers of atrial and ventricular distension due to increased intracardiac pressure. The New York Heart Association (NYHA) developed a 4-stage functional classification system for congestive heart failure (CHF) based on the severity of the symptoms. Studies have demonstrated that the measured concentrations of circulating BNP and/or NT-proBNP increase with the severity of CHF based on the NYHA classification.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Males

< or =45 years: 10-51 pg/mL

46 years: 10-53 pg/mL

47 years: 10-55 pg/mL

48 years: 10-56 pg/mL

49 years: 10-58 pg/mL

50 years: 10-59 pg/mL

51 years: 10-61 pg/mL

52 years: 10-62 pg/mL

53 years: 10-64 pg/mL

54 years: 10-67 pg/mL

55 years: 10-68 pg/mL

56 years: 10-70 pg/mL

57 years: 10-71 pg/mL

58 years: 10-73 pg/mL

59 years: 10-76 pg/mL

60 years: 10-77 pg/mL

61 years: 10-79 pg/mL

62 years: 10-82 pg/mL

63 years: 10-83 pg/mL

64 years: 10-85 pg/mL

65 years: 10-88 pg/mL

66 years: 10-89 pg/mL

67 years: 10-92 pg/mL

68 years: 10-95 pg/mL

69 years: 10-97 pg/mL

70 years: 10-100 pg/mL

71 years: 10-103 pg/mL

72 years: 10-104 pg/mL

73 years: 10-107 pg/mL

74 years: 10-110 pg/mL

75 years: 10-113 pg/mL

76 years: 10-116 pg/mL

77 years: 10-119 pg/mL

78 years: 10-122 pg/mL

79 years: 10-125 pg/mL

80 years: 10-128 pg/mL

81 years: 10-131 pg/mL

82 years: 10-135 pg/mL

> or =83 years: 10-138 pg/mL

 

Females

< or =46 years: 10-140 pg/mL

47 years: 10-141 pg/mL

48 years: 10-144 pg/mL

49 years: 10-146 pg/mL

50 years: 10-149 pg/mL

51 years: 10-150 pg/mL

52 years: 10-152 pg/mL

53 years: 10-155 pg/mL

54 years: 10-157 pg/mL

55 years: 10-160 pg/mL

56 years: 10-162 pg/mL

57 years: 10-166 pg/mL

58 years: 10-168 pg/mL

59 years: 10-171 pg/mL

60 years: 10-173 pg/mL

61 years: 10-177 pg/mL

62 years: 10-179 pg/mL

63 years: 10-183 pg/mL

64 years: 10-185 pg/mL

65 years: 10-189 pg/mL

66 years: 10-193 pg/mL

67 years: 10-196 pg/mL

68 years: 10-199 pg/mL

69 years: 10-202 pg/mL

70 years: 10-206 pg/mL

71 years: 10-210 pg/mL

72 years: 10-214 pg/mL

73 years: 10-218 pg/mL

74 years: 10-222 pg/mL

75 years: 10-227 pg/mL

76 years: 10-230 pg/mL

77 years: 10-235 pg/mL

78 years: 10-239 pg/mL

79 years: 10-244 pg/mL

80 years: 10-248 pg/mL

81 years: 10-253 pg/mL

82 years: 10-258 pg/mL

> or =83 years: 10-263 pg/mL

Interpretation Provides information to assist in interpretation of the test results

<50 years of age

NT-proBNP values <300 pg/mL have a 99% negative predictive value for excluding acute congestive heart failure (CHF). A cutoff of 1,200 pg/mL for patients with an eGFR <60 yields a diagnostic sensitivity and specificity of 89% and 72% for acute CHF. NT-proBNP values >450 pg/mL are consistent with CHF in adults under 50 years of age.

50-75 years of age

NT-proBNP values <300 pg/mL have a 99% negative predictive value for excluding acute CHF. A cutoff of 1,200 pg/mL for patients with an eGFR <60 yields a diagnostic sensitivity and specificity of 89% and 72% for acute CHF. A diagnostic NT-proBNP cutoff of 900 pg/mL has been suggested in adults 50 to 75 years of age in the absence of renal failure.

>75 years of age

NT-proBNP values <300 pg/mL have a 99% negative predictive value for excluding acute CHF. A cutoff of 1,200 pg/mL for patients with an eGFR <60 yields a diagnostic sensitivity and specificity of 89% and 72% for acute CHF. A diagnostic NT-proBNP cutoff of 1,800 pg/mL has been suggested in adults over 75 years of age in the absence of renal failure.

 

NT-Pro BNP levels are loosely correlated with New York Heart Association (NYHA) functional class (see Table).

 

Interpretive Levels for CHF

Functional Class

5th to 95th Percentile

Median

I

31-1,110 pg/mL

377 pg/mL

II

55-4,975 pg/mL

1,223 pg/mL

III

77-26,916 pg/mL

3,130 pg/mL

IV

*

*

*In a Mayo Clinic study of 75 patients with CHF, only 4 were characterized as Class IV. Accordingly, range and median are not provided.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Lack of NT-proBNP elevations have been reported if congestive heart failure is very acute (first hour) or occurs with ventricular inflow obstruction (hypertrophic obstructive cardiomyopathy, mitral stenosis, atrial myxoma).

Supportive Data

The Roche NT-proBNP assay is automated and more precise than the Biosite BNP assay used previously. In addition, in vitro NT-proBNP is more stable than BNP.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Januzzi JL, van Kimmenade R, Lainchbury J: NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1,256 patients; The International Collaborative of NT-proBNP Study. Eur Heart J 2006;27:330-337

2. van Kimmenade R, Pinto YM, Bayes-Genis A: Usefulness of intermediate amino-terminal pro-brain natriuretic peptide concentrations for diagnosis and prognosis of acute heart failure. Am J Cardiol 2006;98:386-390

3. DeFilippi C, van Kimmenade R, Pinto YM: Amino-terminal pro-B-type natriuretic peptide testing in renal disease. Am J Cardiol 2008;101[suppl]:82A- 88A