What is the substance ejected through mouth and used for diagnostic purposes in respiratory disorders?

The substance ejected through mouth and used for diagnostic purposes in respiratory disorders is called sputum. Sputum is a mixture of saliva and mucus that is produced in the lungs and airways. It can contain cells, bacteria, viruses, and other particles. Sputum analysis can be used to diagnose a variety of respiratory conditions, including pneumonia, bronchitis, and tuberculosis.