Test ID: PBNP
NT-Pro B-Type Natriuretic Peptide (BNP), Serum
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
An aid in the diagnosis of congestive heart failure
Method Name A short description of the method used to perform the test
Electrochemiluminescence Immunoassay
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
NT Pro BNP
ProBNP (B-Type Natriuretic Peptide)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Additional Information: Patient's age and sex are required.
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 365 days |
| Refrigerated | 7 days |
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 (Pro BNP). 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-Pro BNP) is rapidly cleaved by the enzymes corin and/or furin to release the active 32 amino acid peptide (BNP).(2)
Both BNP and NT-Pro BNP 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-Pro BNP increase with the severity of CHF based on the NYHA classification.(4,5,6)
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
NT-pro BNP values <300 pg/mL have a 98% negative predictive value for excluding acute congestive heart failure (CHF).
NT-pro BNP values >450 pg/mL are consistent with CHF in adults under age 50; while in adults aged 50 years and older a diagnostic cut-off of 900 pg/mL has been suggested in the absence of renal failure.
NT-Pro BNP levels are loosely correlated with 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-Pro BNP 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-Pro BNP assay is automated and more precise than the Biosite BNP assay used previously. In addition, in vitro NT-Pro BNP 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
Method Description Describes how the test is performed and provides a method-specific reference
This is an automated, double-incubation sandwich assay. In the first incubation, antigen from the patient specimen reacts with biotinylated monoclonal sheep NT-Pro BNP antibody and monoclonal NT-Pro BNP antibody labeled with ruthenium complex. During the second incubation, streptavidin-labeled microparticles are added, and the resulting complex is bound to the solid-phase via biotin-streptavidin interaction. The resulting reaction mixture is aspirated into the measuring cell where the microparticles are magnetically captured onto the surface of an electrode. Unbound substances are washed away. Voltage is then applied to the electrode, which induces chemiluminescent emission that is measured by a photomultiplier. Results are obtained by comparing this measurement against the calibration curve. The Roche E Modular NT-ProBNP assay standardization is traceable to an internal Roche standard. Assigned values for calibrators are traceable to this standardization.(Package insert: ProBNP II, Roche Diagnostics Corporation, Indianapolis IN)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Sunday; Continuously
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83880
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| PBNP | NT-Pro BNP, S | 33762-6 |
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