The cytologic examination of sputum and bronchial secretions has become a reliable method for detecting early lung cancer. A number of benign chest conditions also can be recognized through specific morphologic observations. The need for examining 5 sputum samples to achieve optimum sensitivity has discouraged clinical interest in pulmonary cytology. A new method has been developed whereby a single concentrated sample has yielded an accuracy equivalent to 4 samples smeared by earlier methods. The new method employs trypsin as a mucolytic agent. The concentrated sediment obtained after tryptic digestion can be used in concomitant bacteriological and mycological examination. It is believed that the increased convenience and accuracy of this method will encourage the use of cytologic methods in the diagnosis of diseases of the chest.
Farber SM. Clinical Appraisal of Pulmonary Cytology. JAMA. 1961;175(5):345-348. doi:10.1001/jama.1961.03040050001001