Investigation of an N‐Terminal Prohormone of Brain Natriuretic Peptide Point‐of‐Care ELISA in Clinically Normal Cats and Cats With Cardiac Disease

Abstract

BackgroundN‐terminal prohormone of brain natriuretic peptide (NT‐proBNP) concentrations may be increased in cats with various cardiac disorders. The point‐of‐care (POC) ELISA assay uses the same biologic reagents as the quantitative NT‐proBNP ELISA. Previous studies have evaluated the sensitivity and specificity of the POC ELISA in cats with cardiac disease.ObjectivesTo prospectively evaluate the diagnostic utility of the POC ELISA in a select population of cats.AnimalsThirty‐eight client‐owned cats presented to the University of Florida Cardiology Service for cardiac evaluation. Fifteen apparently healthy cats recruited as part of another study.MethodsPhysical examination and echocardiography were performed in all cats. The POC ELISA was assessed visually as either positive or negative by a reader blinded to the echocardiographic findings, and results were analyzed relative to quantitative assay results.ResultsTwenty‐six cats were diagnosed with underlying cardiac disease, and 27 cats were considered free of cardiac disease. Cats with cardiac disease included: 21 with hypertrophic cardiomyopathy, 2 with unclassified cardiomyopathy, 2 with restrictive cardiomyopathy, and 1 with 3rd degree atrioventricular (AV) block. The POC ELISA differentiated cats with cardiac disease with a sensitivity of 65.4% and specificity of 100%.Conclusions and Clinical ImportanceThe POC NT‐proBNP ELISA performed moderately well in a selected population of cats. A negative test result cannot exclude the presence of underlying cardiac disease, and a positive test result indicates that cardiac disease likely is present, but further diagnostic investigation would be indicated for a definitive diagnosis.

Effect of feline characteristics on plasma N‐terminal‐prohormone B‐type natriuretic peptide concentration and comparison of a point‐of‐care test and an ELISA test

“…The POCT becomes abnormal within a transition interval rather than a set cutoff value, which is a limitation. In our study, the transition interval was found to between 69 and 117 pmol/L, which is slightly lower than a previous study in which the transition occurred between 108 and 122 pmol/L 9 but different from another study in which the transition interval was between 150 and 200 pmol/L 11 . However, the SE and the SP for the ELISA and the POCT were similar, therefore the POCT results seem reliable.…”

“…The POCT showed a higher false‐negative rate than true positive rate, which implies that a cat with a normal POCT may need further evaluation by echocardiography to exclude mild HCM. Similar results have been reported previously for both the POCT and the quantitative ELISA in cats with cardiac disease 9,11,14 …”

“…The transition interval when the POCT becomes positive has been reported to range between 108 and 200 pmol/L 9,11 . Abnormal ELISA or POCT NT‐proBNP results in cats have been shown to be associated with cardiac disease, implying that further diagnostic evaluation by echocardiography is indicated 5,9‐14 . Previous studies have reported that both quantitative and semiquantitative NT‐proBNP concentrations can discriminate cats with cardiac disease from healthy cats.…”

“…Previous studies have reported that both quantitative and semiquantitative NT‐proBNP concentrations can discriminate cats with cardiac disease from healthy cats. Sensitivity (SE) has been described to vary between 65.4 and 93.9%, and specificity (SP) between 87.8 and 100% 9‐12,14,15 . These studies included cats with various cardiac diseases.…”

ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats

“…The quantitative NT‐proBNP assay is not recommended for differentiating normal cats from cats with mild to moderate HCM (LOE high) . The point‐of‐care assay can be considered in cats with suspected subclinical cardiomyopathy, but its principal value is in differentiating cats with severe subclinical cardiomyopathy from normal cats or cats with only mild disease (LOE high) …”