A-021 Evaluation of a Novel N Terminal Pro B Type Natriuretic Peptide Assay as an aid in the Diagnosis of Acute Heart Failure in the Emergency Department
Authors: Peacock W F , Alahapperuma D , Allen B , Christenson R , Guidi J , Headden G , Winden N , Januzzi J L 
Published: October 2024

Abstract

Background
The signs and symptoms of acute heart failure (AHF) may overlap with other conditions and lead to diagnostic difficulty in the undifferentiated patient with dyspnea. The particularly high negative predictive value (NPV) of natriuretic peptides (NPs) in excluding AHF have rendered these assays especially useful in evaluating dyspnea in acute care setting. This study was conducted to assess the diagnostic performance of a novel N-terminal pro-B type natriuretic peptide (NT-proBNP) assay in the intended use patient population in the emergency department (ED).

Methods
A multicenter study was conducted in the U.S. on individuals presenting to the ED with dyspnea and a suspicion of AHF. Blood specimens were collected and tested using the Beckman Coulter Access NT-proBNP assay on the DxI 9000 Immunoassay Analyzer. Test results were compared to an adjudicated diagnosis clinical endpoint performed by an independent Clinical Events Committee blinded to the Access NT-proBNP result. Performance included NPV and sensitivity of an age-independent cut point of &lt;300 ng/L to exclude AHF, and the positive predictive value (PPV) of the age-dependent cut points of &gt;450, &gt;900, and &gt;1800 ng/L for ages &lt;50 years, 50-75 years, and &gt;75 years, respectively, for the diagnosis of AHF. The sample size required to achieve a 95% two tailed confidence interval (CI) was 150 subjects per age group to provide clinical performance at 90% (±10%) sensitivity. Sample size was based upon CLSI EP24-A2, Assessment of the Diagnostic Accuracy of Laboratory Tests Using Receiver Operating Characteristic Curves. Sensitivity and specificity were calculated at a series of cutoff points and plotted in separate receiver operation curves (ROC) for an overall age-independent rule-out analysis and for individual age-dependent groups separately. Area under the receiver operator characteristic curve (AUROC) was reported with 95% 2-sided CI. NPV and PPV with respective 95% 2-sided score CI was computed for the overall age-independent cut point and for each age group cohort.

Results
Of 490 enrolled patients, 41% were adjudicated with AHF with a median (Q1, Q3) age of 60 (47-76) years, and distributions of 46.1% female, 60.8% White and 38.2% Black. The assay had an AUROC for AHF of 0.88 (P&lt;0.001), comparable to other commercially available NT-proBNP assays. The rule-out cut point of &lt;300 ng/L had 96% sensitivity and NPV of 95%. Age-dependent cut points had sensitivity of 84%, 90%, and 87%, specificity of 81%, 70% and 61%, and PPV of 72%, 62%, and 74%, respectively.

Conclusions
The Access NT-proBNP assay demonstrated high clinical performance in the diagnosis and exclusion of acute HF in the undifferentiated dyspneic patient population and performed similarly well to validated assays used in current clinical practice. Given the continued increase in importance and reach of natriuretic peptide testing, these results are useful to extend availability of this assay to a larger audience.