The document discusses sputum examination and sputum smear microscopy. Sputum is mucus coughed up from the lower airways that is used for microbiological and cytological investigations of respiratory infections and systems. A good sputum sample is purulent with white blood cells, debris and viscous liquid. Sputum collection and smearing procedures are outlined as well as staining techniques like fluorescent staining for acid-fast bacilli examination to detect infections like tuberculosis. The standard operating procedure for sputum smear microscopy and common bacteria detected from cultures are also summarized.