Clinical Performance of an N-Terminal Pro-B-Type Natriuretic Peptide Assay in Acute Heart Failure Diagnosis

Background: We evaluated the Vitros (R) Immunodiagnostic Products N-terminal pro B-type natriuretic peptide (NT-proBNP) II assay for aiding in diagnosis of heart failure (HF) in patients with acute dyspnea. Methods: Serum concentrations of NT-proBNP were measured in patient samples from 20 emergency departments across the United States. Study endpoints included sensitivity, specificity, likelihood ratios, and predictive values for diagnosis of acute HF according to age-stratified cutoffs (450, 900, and 1800 pg/mL), and a rule-out age-independent cutoff (300 pg/mL). Additional measures were area under the curve (AUC) for receiver operating characteristic (ROC) curves. Results were also interpreted in patient subgroups with relevant comorbidities, and gray zone/intermediate assay values. Results: Of 2200 patients, 1095 (49.8%) were diagnosed with HF by clinical adjudication. Sensitivity and specificity for Vitros NT-proBNP II ranged from 84.0% to 92.1%, and 81.4% to 86.5%, respectively, within and across age groups, and positive predictive values were 80.4% to 85.7%. Using the rule-out cutoff, the negative predictive value was 97.9%, with a negative likelihood ratio of 0.02. In subgroups with comorbidities potentially affecting NT-proBNP concentrations, sensitivities ranged from 82.6% to 89.5%, and AUCs for ROC curves were 0.899 to 0.915. Conclusions: The Vitros NT-proBNP II assay demonstrated excellent clinical performance using age-stratified cutoffs along with other clinical information for supporting diagnosis of HF, and can rule out HF with a high negative predictive value using the age-independent cutoff. The assay retained utility in patient subgroups with conditions that influence NT-proBNP concentration, and for those with gray zone results. ClinicalTrials.gov Registration Number: NCT03548909.