Reliability and accuracy of point-of-care amino-terminal probrain natriuretic peptide in congestive heart failure patients

Background: Globally, role of amino-terminal pro-brain natriuretic peptide (NT pro-BNP) in diverse aspects of Congestive Heart Failure (CHF) has gained near-consensus status. Such experience is rare in many parts of Africa, and levels may be affected by ethnicity. Aim/Objectives: To determine NT pro-BNP levels in Nigerian healthy adults and hospitalised CHF patients; in order to establish its diagnostic accuracy. Methods: Controls and CHF patients were examined clinically, with trans-thoracic echocardiography; while plasma NT pro-BNP was measured by a point-of care-immunoassay system (Cardiac Reader^R). We compared the diagnostic performance of our study-derived NT pro-BNP reference value with others. Main outcome: Obtain reference value of NT pro-BNP and compare its diagnostic performance with recommended product value of 125 pg/mL. ResultsParticipants were 42 CHF patients matched for age (p=0.26) and gender (p=0.78) with 30 controls. NT pro-BNP levels of controls differed significantly by gender (females: 64.8 ±12.3 versus males: 98.2 (54.8), p<.05); and by CHF status (86.43±43.6 versus 1915 ±1082.1 pg/mL, p<.001). NT pro-BNP demonstrated negative correlation with left ventricular function (r=-0.5, p<.05). Our study NT pro-BNP reference value of 171 pg/mL yielded sensitivity, specificity, NPV, PPV of 88.1%, 93.3%, 90.3%, 95.2%, respectively, performing better than manufacturer's recommended value of 125 pg/mL(sensitivity 85.7%, specificity 86.7%, NPV 87.1%, and PPV 92.5% respectively. Conclusions: NT pro-BNP values were significantly higher in CHF patients; and demonstrated significant negative association with left ventricular function. Our point-of care reference value demonstrated better diagnostic performance than manufacturer's cut-off value. This calls for further local studies, using the new cut-off value.