NT Pro BNP Testing
The NT Pro BNP blood test will act as a ‘rule out‘ test for the diagnosis of left ventricular systolic dysfunction.
Measure serum natriuretic peptides (N-terminal pro-B-type natriuretic peptide [NTproBNP])) in patients with suspected heart failure without previous MI in the following circumstances.
Patients presenting with symptoms of heart failure, having been examined and a resting ECG and chest x – ray undertaken.
The following patients will not be eligible to have BNP testing:
Patients presenting with symptoms of heart failure, who have had a previous documented myocardial infarction, resulting in inpatient admission and treatment. Refe for further investigation to the appropriate heart failure service.
The test should not be used as a monitoring process, but a ‘rule out’ test. Therefore patients with a confirmed diagnosis of heart failure and on a heart failure register should not be tested.
In addition BNP testing may not be appropriate in patients in which:
A murmur is heard
The pulse is irregular – Atrial Fibrillation
Bradycardia or tachycardia i.e. heart rate < 60 or > 100
Or a significant abnormality is detected on the ECG
In the above cases, the patient should be referred for further investigation to either:
The heart failure service where heart failure is clinically thought to be the main problem
Cardiology outpatients where the underlying cause such as valvular heart disease is thought to be important.
Refer patients with suspected heart failure and previous myocardial infarction (MI) urgently, to have echocardiography and specialist assessment within 2 weeks.
Because very high levels of serum natriuretic peptides carry a poor prognosis, refer patients with suspected heart failure and a NTproBNP level above 2000 pg/ml urgently for echocardiography and specialist assessment within 2 weeks.
For advice on urgent referral please see the Heart Failure section of Remedy.
Interpretation of results
Heart failure is unlikely if the NTproBNP level is:
Men under 70yr <100pg/ml
Women under 70yr <150pg/ml
All 70yr or over <300pg/ml
If so, consider an alternative diagnosis, however if still thinking heart failure as a possible diagnosis then refer to the community heart failure service for a comprehensive assessment including echo.
Requesting NT Pro BNP Testing
Blood samples need to be taken in primary care, with the test, where possible be ordered through the ICE system. This should include a pre – order requirement within the ordering system that both a full examination and resting ECG has been taken. Urgent testing will be available after discussion with the Clinical Biochemistry laboratory.
The blood samples will be picked up using the existing pathology systems and processes.
Why can’t patients who have Atrial Fibrillation and suspected heart failure have BNP testing?
Atrial Fibrillation tends to raise the BNP level so the cut-off values in Atrial Fibrillation are less reliable. Therefore if a patient has Atrial Fibrillation and suspected heart failure they should not have BNP but be referred to echo and specialist HF opinion at the Community Heart Failure Service.
What if my patient had a heart attack years ago, can he have BNP now?
NICE guidance recommends that for patients with any previous MI do not do BNP and refer for echo. Therefore if the patient has a documented MI resulting in an IP admission and treatment at all in their medical history, do not conduct BNP but refer for echo to the community heart failure service.
What about results?
Tests will be turned around within three working days (on average). Turnaround time is defined as from receipt in the laboratory to electronic reporting back to primary care. If results are normal or moderately raised then practices should be informed through routine blood results however, if >2000 practices will be called the same day with the results, with an expectation that practices act on this information the same day.