Amino-terminal pro-B-type natriuretic peptide testing in renal disease.

Concentrations of amino-terminal pro-B-type natriuretic peptides (NT-proBNP) are typically higher in patients with chronic kidney disease (CKD) than in those without CKD. These elevated levels of NT-proBNP in patients with CKD do not simply reflect the reduced clearance of the peptide; rather, they largely reflect a true-positive finding, identifying the presence of heart disease in these patients, while similarly indicating prognosis as well. Although modestly stronger inverse correlations exist between renal function and NT-proBNP compared with B-type natriuretic peptide (BNP), the dependence of both peptides on renal clearance is similar. Across the range of CKD, correlations between BNP and NT-proBNP remain strong, and the prognostic impact of NT-proBNP in patients with CKD is preserved. When evaluating the patient with acute dyspnea and CKD, both BNP and NT-proBNP are affected similarly, with higher decision limits necessary compared with patients with preserved renal function. Importantly, when using NT-proBNP to evaluate a patient with dyspnea and impaired renal function, the recommended cut points of 450, 900, and 1,800 ng/L for those aged <50, 50-75, and >75 years, respectively, do not require further adjustment for renal function. Thus, NT-proBNP testing remains useful for the diagnostic and prognostic evaluation of patients with CKD.