Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
NT-proBNP - (P)
Test Code: NBNP
Clinical Information:
Test Indications: 
• NT-proBNP has a very high diagnostic accuracy in discriminating heart failure (HF) from other causes of dyspnea: the higher the value, the higher the likelihood that dyspnea is caused by HF.
• NT-proBNP testing can be considered for patient presenting with atraumatic dyspnea without obvious cause, where history, physical exam, CXR and POCUS are not diagnostic or not available.

• Perioperative NT-proBNP is a prognostic indicator for post-surgical outcomes and can be used to identify high risk patients and plan care appropriately.


Cautions:
• Laboratory Reports provide age specific cutoff values indicating probability of Heart Failure in adults. These are not “normal” reference values.  See reference values section below.
• NT-proBNP is a marker of myocardial stress, as such may be elevated among patients with severe respiratory illnesses typically in the absence of elevated filling pressures or clinical heart failure. 
• NT-proBNP cannot identify the underlying cause of HF and, therefore, if elevated, must always be used in conjunction with cardiac imaging.
• NT-proBNP measurements should always be used in conjunction with all other clinical information.


Resources:

The Canadian Cardiovascular Society – Is it Heart Failure and What Should I Do?  88067 CCS - HF Eng 2021 REV10  https://ccs.ca/wp-content/uploads/2021/05/2021-HF-Gui-PG-EN-2.pdf  


References:

1. Ezekowitz JA, O'Meara E, McDonald MA, et al. 2017 Comprehensive update of the Canadian Cardiovascular Society Guidelines for the management of heart failure. Can J Cardiol. 2017;33(11):1342-1433.

2. Kozhuharov N, et al. Clinical effect of obesity on N-terminal pro-B-type natriuretic peptide cut-off concentrations for the diagnosis of acute heart failure. European Journal of Heart Failure (2022) 24, 1545–1554

3. Welsh P, et al. Reference Ranges for NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) and Risk Factors for Higher NT-proBNP Concentrations in a Large General Population Cohort. Circ Heart Fail. (2022) Oct;15(10):e009427.

4. Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery. Can J Cardiol 2017:22;17-32


Clinical Practice Change: NT-proBNP Testing
Collection Devices:
Specimen Required:
Plasma: 2.0 mL
Pediatric Plasma: 0.2 mL

Refrigerated: 6 days

Frozen: 2 years

 
Referral:

Sample must be transferred to an aliquot tube. Send frozen if sample will not be received at testing site within 48 hours of collection.
Requisition:
Reference Values:
All results are flagged as abnormal (high) at ≥ 300 pg/mL
 
All Ages
< 300 pg/mL: Heart Failure is unlikely in Acute Care setting. In ambulatory care, values <125 pg/mL can be used to rule out heart failure.

 
Age < 50 yr
300-450 pg/mL:  Heart Failure is possible, but other diagnoses should be considered.
> 450 pg/mL:  Consider Heart Failure or other cause of myocardial stress.  Elevation may be due to severe respiratory illnesses, including pulmonary embolism. Clinical correlation required.
 
Age 50 to 75 yr
300-900 pg/mL:  Heart Failure is possible, especially if NT-proBNP is > 450 pg/mL. Other diagnoses should be considered.
> 900 pg/mL: Consider Heart Failure or other cause of myocardial stress.  Elevation may be due to severe respiratory illnesses, including pulmonary embolism. Clinical correlation required
 
Age > 75 yr
300-1800 pg/mL:  Heart Failure is possible, especially if NT-proBNP > 900 pg/mL. Other diagnoses should be considered.
>1800 pg/mL: Consider Heart Failure or other cause of myocardial stress.  Elevation may be due to severe respiratory illnesses, including pulmonary embolism. Clinical correlation required.

 

Laboratory Reports provide age specific cutoff values indicating probability of Heart Failure in adults. These are not “normal” reference values.  In healthy individuals NT-proBNP results are dependent on age (young children and older adults have higher values), gender (females have higher values then males) and body size.


Patients with heart failure and obesity show lower than expected NT-proBNP results.


Method of Analysis: Roche Cobas Elecsys proBNP II (Immunoassay)


Reference(s): The 2014 Canadian Cardiovascular Society Heart Failure Management Guidelines Focus Update: Anemia, Biomarkers, and Recent Therapeutic Trial Implications. Moe G et al. Canadian Journal of Cardiology. 2015; 31: 3-16
Availability:
STAT (only if site has onsite NT-proBNP testing) or Routine Testing performed at HSC, SBH, WML(Brandon)
See Also:
More Information: