This document provides guidelines for the initial and serial evaluation of patients with heart failure (HF). It recommends obtaining a thorough history and physical exam, assessing vital signs and weight at each visit, performing an electrocardiogram and basic lab tests initially, and using biomarkers like BNP and NT-proBNP to aid in diagnosis, establish prognosis, and guide therapy for both acute and chronic HF patients. It also recommends using validated risk scores to estimate mortality risk in ambulatory or hospitalized HF patients. The guidelines provide classifications for HF and recommendations for diagnostic testing and use of biomarkers at different stages of care.