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HelpTest Code PBNP1 NT-Pro B-Type Natriuretic Peptide, Serum
Necessary Information
Patient's age and sex are required.
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions:
1. Serum gel tubes should be centrifuged within 2 hours of collection.
2. Red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial within 2 hours of collection.
Useful For
Aiding in the diagnosis of congestive heart failure using serum specimens
Testing Algorithm
For more information see Amyloidosis: Laboratory Approach to Diagnosis
Special Instructions
Method Name
Electrochemiluminescence Immunoassay
Reporting Name
NT-Pro BNP, SSpecimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 365 days | |
| Refrigerated | 7 days |
Reject Due To
| Gross hemolysis | Reject |
Clinical Information
B-type natriuretic peptide (formerly 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 or pressure overload, the N-terminal (NT) piece of 76 amino acids (NT-proBNP) is rapidly cleaved by the enzymes corin and 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 NT-proBNP increase with the severity of CHF based on the NYHA classification.
Reference Values
Males
0-2 day: 321-11,987 pg/mL
3-11 day: 263-5918 pg/mL
12 day-1 month: Not applicable
2 month-1 year: 37-646 pg/mL
2 years: 39-413 pg/mL
3 years-6 years: 23-289 pg/mL
7 years-14 years: ≤157 pg/mL
15 years-18 years: ≤158 pg/mL
19-39 years: <79 pg/mL
40-44 years: ≤72 pg/mL
45-54 years: ≤87 pg/mL
55-64 years: ≤88 pg/mL
≥65 years: ≤540 pg/mL
Females
0-2 day: 321-11,987 pg/mL
3-11 day: 263-5918 pg/mL
12 day-1 month: Not applicable
2 month-1 year: 37-646 pg/mL
2 years: 39-413 pg/mL
3 years-6 years: 23-289 pg/mL
7 years-14 years: < or=157 pg/mL
15 years-18 years: ≤158 pg/mL
19-39 years: <160 pg/mL
40-44 years: ≤162 pg/mL
45-54 years: ≤141 pg/mL
55-64 years: ≤226 pg/mL
≥65 years: ≤540 pg/mL
Interpretation
Under 50 years of age:
N-terminal pro B-type natriuretic peptide (NT-proBNP) values below 300 pg/mL have a 99% negative predictive value for excluding acute congestive heart failure (CHF). A cutoff of 1200 pg/mL for patients with an estimated glomerular filtration rate (eGFR) below 60 yields a diagnostic sensitivity and specificity of 89% and 72% for acute CHF. NT-proBNP values greater than 450 pg/mL are consistent with CHF in adults under 50 years of age.
50-75 years of age:
NT-proBNP values below 300 pg/mL have a 99% negative predictive value for excluding acute CHF. A cutoff of 1200 pg/mL for patients with an eGFR below 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 for adults 50 to 75 years of age in the absence of kidney failure.
Over 75 years of age:
NT-proBNP values below 300 pg/mL have a 99% negative predictive value for excluding acute CHF. A cutoff of 1200 pg/mL for patients with an eGFR below 60 yields a diagnostic sensitivity and specificity of 89% and 72% for acute CHF. A diagnostic NT-proBNP cutoff of 1800 pg/mL has been suggested for adults over 75 years of age in the absence of kidney failure.
NT-Pro BNP levels are loosely correlated with New York Heart Association (NYHA) functional class (see Table).
Table. Interpretive Levels for CHF
|
Functional class |
5th to 95th percentile |
Median |
|
I |
31-1110 pg/mL |
377 pg/mL |
|
II |
55-4975 pg/mL |
1223 pg/mL |
|
III |
77-26,916 pg/mL |
3130 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
Lack of N-terminal-pro B-type natruretic peptide (NT-proBNP) elevations have been reported if congestive heart failure is very acute (first hour) or occurs with ventricular inflow obstruction (eg, hypertrophic obstructive cardiomyopathy, mitral stenosis, atrial myxoma).
Method Description
This is an automated, double-incubation sandwich assay. In the first incubation, antigen from the patient specimen reacts with biotinylated monoclonal sheep N-terminal pro brain natriuretic peptide (NT-proBNP) antibody and monoclonal NT-proBNP 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.
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.(Package insert: ProBNP II, Roche Diagnostics; V 12.0. 07/2021)
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 2 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
83880
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| PBNP1 | NT-Pro BNP, S | 83107-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| PBNP1 | NT-Pro BNP, S | 83107-3 |