Lung ultrasound (LUS) is fundamental in the evaluation of patients with dyspnoea and respiratory failure. It has gained broad acceptance among physicians specializing in intensive care, emergency medicine, pulmonary care and internal medicine [[1], [2], [3]]. Furthermore, LUS is a rapid, bedside, noninvasive, radiation-free diagnostic tool that clinicians can use as an integrated part of the initial clinical assessment and monitoring. With the ongoing development of increasingly portable ultrasound technology, LUS is expected to play an increasingly important role in remote areas with limited resources. Previous studies have shown that with proper training, healthcare providers can acquire the competencies required to perform LUS, particularly for diagnosing acute heart failure (AHF) [[4], [5], [6]]. Recently, we demonstrated the association of invasive haemodynamic measurements with B-line count on LUS in patients hospitalized with AHF and found that ≥6 B-lines at discharge had the best discriminating value for the event risk [7]. However, the ability of novice residents to detect residual congestion by LUS after decongestion treatment is poorly understood. The present study aimed to investigate the ability of novice residents (no prior echocardiography experience), who received a brief lecture, to detect residual congestion after decongestion treatment and to provide the degree of agreement for identifying residual congestion using a cut-off value.