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PTD - 181

Test Directory -  BNP (NT-proBNP)


N-terminal pro-b-type natriuretic peptide

Clinical Indications

Pro B-type natriuretic peptide (BNP) is released from the cardiac ventricles in response to stretching of the chamber and is cleaved to form biologically active BNP and N-terminal pro-BNP (NT-proBNP). The assay used at Basildon measures NT-proBNP.
It has been introduced to 'rule-out' suspected heart failure and help select patients requiring cardiac imaging. It is important that it is only requested in patients meeting specific criteria (see below) otherwise many 'false positive' results may be generated which will need follow-up cardiac imaging. 

Request Form

Combined Pathology Blood form (Yellow/Black)


Analysed if requested by GP or specific criteria met.

Specific Criteria

BNP analyses is only available to GPs for investigation of new cases of suspected heart failure. ECG and chest X-ray should have been undertaken and anaemia, renal, liver and thyroid dysfunction excluded.

BNP is also available for A&E/MAU patients on admission with suspected Heart Failure (see pathway). These requests are usually initiated by the Heart Failure team.

Patient Preparation

None required.

Turnaround Time

Same day.




2 ml


Yellow top (SST) tube

Causes for Rejection

Unlabelled sample, not meeting specific criteria

Reference Ranges &

A negative NT-proBNP (< 300 ng/L <75 years age and < 450 ng/L if 75 years age or over) has a very high negative predictive value (>98%) and virtually excludes left ventricular systolic dysfunction. A positive NT-proBNP indicates the need for further investigation including echocardiography.

Please see patient pathway for interpretation of BNP results on patients admitted with suspected Heart Failure .

Lab. Handling

Processing: Test code BNP. Analysed from primary tube and stored at 4C in the cold room (CB23). (NOBNP & save in separating freezer (CB40) at -20C, saved frozen rack)


Version 1.0 / April 2014                                                                                                          Approved by: Consultant Biochemist