Updated October 28, 2014.

Definition: Sputum Cytology

Sputum cytology refers to the examination of sputum (mucous) under a microscope to look for abnormal or cancerous cells.

Sputum differs from saliva, in that it contains cells that line the respiratory passages.

Sputum is usually collected by forcefully coughing into a container, or during a bronchoscopy. While this procedure has not been found to be an effective screening test for lung cancer, when done on someone with symptoms, it can sometimes result in a diagnosis of lung cancer.