Nationwide survey in Japan of the causative diseases of bloody sputum and hemoptysis in departments of respiratory medicine at university hospitals and core hospitals

The Guidelines for the Management of Cough and Sputum (2019) of the Japanese Respiratory Society (JRS) were the first internationally published guidelines for the management of sputum. However, the data used to determine the causative diseases of bloody sputum and hemoptysis in these guidelines were not obtained in Japan.