The aim of the study was to evaluate the compliance of the number of B-lines on focused lung ultrasound with the clinical heart failure classification of the New York Heart Association (NYHA) and NT-proBNP levels in the emergency department. This prospective study was conducted in a tertiary university hospital emergency department. Patients over 18 years of age complaining of shortness of breath or heart failure diagnosis between January 2016 and July 2016. The number of B-lines according to the BLUE point regions was measured. Correlations between the clinical heart failure stage, NT-proBNP level and number of B-lines on ultrasonography were analyzed. Of the 143 patients, 92 (64.3%) were male and 51 (35.7%) were female. The median age was 73.00 (66.00-79.00). There was a very strong correlation between the number of B-lines and NYHA stages for each region (r > 0.85 for all variables; p <0.001 for all). There was also a strong and direct correlation between the number of B-lines and the NT-proBNP levels for each region (r > 0.70; p <0.001). Regarding the shortness of breath numerical score (r > 0.45; p <0.001), there was an inverse relationship with ejection fraction (EF). The relationship between the EF and BLUE points was moderate, but negative and significant (p <0.001). NT-proBNP levels, the NHYA classification, and lung ultrasound can be used as a tool in the emergency department for a faster diagnosis and decision-making in lung congestion.