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Epic Test Code Informational BNP Fact Sheet.

Last Updated

14-Feb-22 

BNP Facts

  • Congestive Heart Failure (CHF): The inability of the heart to pump sufficient amounts of blood from the ventricles (lower chambers) to meet the metabolic demands of the body.
  • CHF is difficult to diagnose accurately
  • The signs and symptoms are not always specific for CHF
  • Echocardiography results typically are not available 24-hours- 7 days per week.
  • BNP (B-Type Natriuretic Peptide) and NT-proBNP (N-terminal pro-B-Type Natriuretic peptide) are biomarkers that aid in the diagnosis of CHF, both reflect heart failure severity.
  • Release of NT-proBNP and BNP is in a 1:1 ratio. BNP and NT-proBNP are clinically equivalent.
  • BNP is a hormone produced by the body and has a role in the physiology of the heart. It is produced by cells in the heart ventricles in response to heart failure (inefficient blood pumping), relieving ventricle wall stress. Differences between BNP and NT-proBNP are shown below.

               Differences

BNP

NT-proBNP

In vivo half-life

20 mins

1-2 hrs

Correlation with NYHA Classification

              Yes

Yes

Clearance from body

Binds to endopeptidases and to receptor sites in the kidneys. Independent of renal function

Excreted by kidneys Affected by renal function

Cross reactivity with Natrecor®

(Natrecor® is a recombinant form of human BNP indicated for the intravenous treatment of patients with acutely decompensated congestive heart failure who have dyspnea)

 

                    Yes

 

No

Change with patient age

Increase with age

Increase with age

Change with patient sex

Females > Males

Females> Males

Change with patient weight

Decrease with increasing BMI

Decrease with increasing BMI

Changes in renal patients after dialysis

Can decrease due crossing dialysis membrane

No change

 

  • The interpretation of NT-proBNP results is not a straightforward “black and white” decision. There is overlap among the results obtained and whether or not the patients are diagnosed “with” or “without” CHF. Results must be evaluated within the respective reference ranges and the clinical picture of the patient.
  • Each Laboratory should establish their own reference range that is representative of their patient population. Results below a cutoff generally provide good negative predictive value thus ruling out a diagnosis of CHF. Values above a cutoff may help diagnose CHF, but further clinical evaluation and data may be warranted.
  • In patients with heart failure, the diagnostic performance of BNP/NT-proBNP is influenced by age, gender and renal function (see table).
  •  Plasma samples (lithium heparin, sodium heparin, and EDTA) can be collected using normal procedures. Serum samples should not be used with the BNP/NT-proBNP method.
  • Entresto® has a direct effect on BNP in blocking neprilysin activity, but has no direct effect on NT-proBNP because BNP (not NT-proBNP) is a substrate of neprilysin, Levels of BNP will reflect the action of the drug, whereas levels of NT-proBNP will reflect the effects of the drug on the heart  (PARADIGM-HF trial, circulation, 2015;131:54-61
  • There is currently no NP assay on the market with a monitoring claim. Using BNP/NT-proBNP for monitoring Entresto® use is considered “off-label” use by the FDA.
  • Variability exists among BNP/NT-proBNP assays. Clinicians cannot assume concentrations of BNP/NT-proBNP will rise after treatment with sacubitril/valsartan. They should keep in mind that changes in one assay may not be superimposable in another. Re-baseline patients with HF is recommended.

 

Additional references

European Heart J. 2012; 33; 1787-1847

Circulation 2015; 131:54-61

European Heart J. 2017; 6:321-328

Clinical Chemistry, 2015; 61:1016-10181

American College of Cardiology/American Heart Assoc. (ACC/AHA)

National Institute for Health and Clinical Excellence (NICE)

American Association for Clinical Chemistry (AACC)