BACKGROUND There is limited information regarding the clinical utility of amino-terminal pro-B-type natriuretic peptide (NT-proBNP) for the detection of left ventricular (LV) dysfunction in the community. We evaluated predictors of circulating NT-proBNP levels and determined the utility of NT-proBNP to detect systolic and diastolic LV dysfunction in older adults. METHODS A population-based sample of 1229 older adults (mean age 69.4 years, 50.1% women) underwent echocardiographic assessment of cardiac structure and function and measurement of circulating NT-proBNP levels. RESULTS Predictors of NT-proBNP included age, female sex, body mass index, and cardiorenal parameters (diastolic dysfunction [DD] severity; LV mass and left atrial volume; right ventricular overload; decreasing ejection fraction [EF] and creatinine clearance). The performance of NT-proBNP to detect any degree of LV dysfunction, including mild DD, was poor (area under the curve 0.56-0.66). In contrast, the performance of NT-proBNP for the detection of EF < or = 40% and moderate-severe DD was strong with area under the curve of > 0.90 regardless of age and sex; history of hypertension, diabetes, coronary artery disease; or body mass category. The ability of NT-proBNP to detect EF < or = 40% and/or moderate-severe DD was optimized by using age/sex-specific limits. Of "false-positive" tests, 88% (124/141) were explained after considering cardiorenal determinants of NT-proBNP levels. CONCLUSIONS Amino-terminal pro-B-type natriuretic peptide is a suboptimal marker of mild LV dysfunction, but performs strongly as a marker of EF < or = 40% and/or moderate-severe DD in the community. Most subjects with a positive NT-proBNP test, using age/sex-specific cutoffs, had prognostically significant abnormalities of cardiac structure or function.