Pro B-type Natriuretic Peptide (NT-proBNP) (Guidelines)

TAM (Treatments and Medicines) NHS Highland
NHS Highland

 

AUDIENCE

  • Primary Care
  • HHSCP only
  • Adults

What is NTproBNP?

NTproBNP is a hormone released by the heart in response to ventricular stretch eg fluid overload. Active BNP hormone causes natriuresis, diuresis and vasodilation.  NTproBNP is an inactive form of BNP, which has been chosen for analysis as it is more stable than BNP.

When should NTproBNP be requested?

  • As part of the investigations for a patient with suspected heart failure.
  • The result should be used to decide if an echochardiography referral is needed.
  • Echocardiography is recommended in patients with suspected heart failure who have a raised NT-proBNP level or an abnormal ECG.

When not to request NTproBNP

Patients with classic signs of acute decompensated heart failure or patients with a previous history of myocardial infarction and symptoms suggestive of heart failure these patients should be referred for urgent ECHO without delay. In order to avoid a delay in referral while waiting for an NTproBNP result.

  • Shortness of breath consistent with other aetiologies.
  • Screening for asymptomatic ventricular dysfunction.
  • General monitoring of treatment for heart failure, except for prescribing Entresto where NTproBNP may be requested under the guidance of Cardiology. If so please indicate this on the request form.

Sample requirements and test information
  • A routine serum (clotted sample) brown top is required for analysis.
  • If the sample will not reach the lab on the day of collection then the sample must be spun and stored in the fridge prior to transportation.
  • Samples for NTproBNP will be analysed twice per week on a Tuesday and Friday.  

Implementation

  • Requests for NTproBNP will vetted to ensure that the test is being used appropriately.
  • You must indicate on the request form the reason for the NTproBNP request.
  • NTproBNP may only be measured once per year on a patient. More frequent requests will be rejected. The Duty Biochemist (ext 5931) should be contacted for exceptional cases.

Interpretation of results and referral

NTproBNP less than 400 ng/L (Below cut-off for ECHO referral as per SIGN guideline)

  • In an untreated patient heart failure is unlikely.
  • Note that obesity, diuretics, ACE inhibitors, Beta-blockers, and ARBs may reduce levels of NTproBNP leading to falsely low levels.
  • If clinical suspicion is high consider further investigation.

NTproBNP greater than or equal to 400 ng/L (Raised Levels)

  • Results may be in keeping with heart failure. Refer for heart failure ECHO.
  • However may be elevated from causes other than heart failure including: left ventricular hypertrophy, ischaemia, tachycardia, right ventricular overload, hypoxaemia (including pulmonary embolism), reduced eGFR (less than 60 mL/min), COPD, diabetes, aged over 70 years), liver cirrhosis.

Abbreviations

Abbreviation Meaning
NT-ProBNP Pro B-type Natriuretic Peptide
ECG Electrocardiogram
ARBs Angiotensin II receptor blockers 
COPD Chronic Obstructive Pulmonary Disorder
eGFR Estimated glomerular filtration rate
U&E Urea and electrolytes
LFT Liver function tests 
TFT Thyroid function tests
FBC Full blood count
ECHO Echocardiogram
ng/L Nanogram/L

Editorial Information

Last reviewed: 05/09/2022

Next review date: 31/08/2025

Author(s): Cardiology.

Version: 2

Approved By: Awaiting approval from TAM Subgroup of ADTC

Reviewer name(s): Prof S Leslie, Consultant Cardiologist and Dr Heidi Mendoza, Clinical Biochemist.

Document Id: TAM133