Therefore, ARNI increases BNP levels12 but not NT-proBNP levels.13 Note that the type of natri- uretic peptide assay that has been performed must be considered during interpretation of natriuretic peptide biomarker levels in patients on ARNI. In 2 studies with ARNI, NT-proBNP levels were reduced,12,14 with the reduction in 1 study being associated with improved A substantial evidence base exists that supports the use of natriuretic peptide biomarkers to assist in the di- agnosis or exclusion of HF as a cause of symptoms (eg, dyspnea, weight gain) in the setting of chronic ambula- or in the setting of acute care with decom- especially when the cause of dyspnea is unclear. The role of natriuretic peptide biomarkers in population screening to detect incident HF is emerg- Elevated plasma levels of natriuretic peptide biomarkers are associated with a wide variety of cardiac and noncardiac causes (Table 2).38 42 Obesity may be as- sociated with lower natriuretic peptide concentrations, and this may modestly reduce diagnostic sensitivity in morbidly obese patients.42 Table 2. Selected Potential Causes of Elevated Natriuretic Peptide Levels38 41 Cardiac HF, including RV syndromes Acute coronary syndromes Heart muscle disease, including LVH Valvular heart disease Pericardial disease Atrial fibrillation Myocarditis Cardiac surgery Cardioversion Toxic-metabolic myocardial insults, including cancer chemotherapy Noncardiac Advancing age Anemia Renal failure Pulmonary: obstructive sleep apnea, severe pneumonia Pulmonary hypertension Critical illness Bacterial sepsis Severe burns Modified from Table 8 of the 2013 HF guideline.9 HF, indicates heart failure; LVH, left ventricular hypertrophy; and RV, right ventricular. 