Diagnostic Equivalence of an N-terminal Pro-Brain Natriuretic Peptide Point-of-Care Test to the Laboratory Method in Patients With Heart Failure and in Reference Populations

Context: Point-of-care assays allow to have analytical results available at the site of patient care delivery such as the emergency department or the intensive care unit. Objective: To demonstrate equivalence in the N-terminal (NT) pro-brain natriuretic peptide (proBNP) concentrations as measured by the point-of-care assay (POC NT-proBNP) in comparison to the laboratory assay (lab NT-proBNP) in patients with heart failure and in a reference population. Design: Multicenter study at 7 sites. The following were eligible for data analysis: 217 patients with heart failure and 189 individuals from a reference population (patients with hypertension, diabetes, chronic obstructive pulmonary disease or asthma, or apparently healthy individuals). For all study participants, NT-proBNP values both with the POC and with the laboratory assay, echocardiographic and spirometry data, and the New York Heart Association classification were available. Results: In method comparisons between POC NT-proBNP and lab NT-proBNP, the slope of the regression line was 0.99 and the correlation coefficient was 0.97. Testing on diagnostic equivalence, POC NT-proBNP versus lab NT-proBNP yielded a mean logarithmic methodical difference of -4.9% in patients with heart failure and +3.5% with the reference population. Using an age-independent cutoff of 125 ng/L, the diagnostic sensitivity of POC NT-proBNP and of lab NT-proBNP was found to be 89%, and the areas under the receiver operating characteristic curves were 0.88 or 0.89, respectively. Conclusions: Our multicenter study has demonstrated the diagnostic equivalence of POC NT-proBNP with lab NT-proBNP both in the diagnosis of heart failure and in the differential diagnosis of a reference population. Consequently, clinical experiences and indications with the laboratory assay could be applied to the POC assay as well.