A STUDY OF TECHNIQUES FOR THE EXAMINATION OF SPUTUM IN A FIELD SURVEY OF CHRONIC BRONCHITIS.

By the time patients with established chronic bronchitis seek advice for their disability, events associated with the development of their first symptoms have usually been forgotten (1). Field studies are necessary, therefore, to observe the early natural history of the disease. For this purpose, simple, valid, and reproducible diagnostic methods are needed, including symptomatic questionnaires, respiratory function tests, and sputum examinations. The use of these methods in field surveys of chronic bronchitis has been studied in considerable detail (2-4) and their value in population prevalence studies demonstrated (5-8). This paper reports further studies of techniques for examining the cellular content of sputum suitable for epidemiologic work. The work, which was undertaken during the early stages of a long-term prospective study of chronic bronchitis, will be described in two parts. First, a simple scheme for the visual grading of sputum purulence was developed and the relation of the grades to cell count was examined. Second, a rapid quantitative method for detecting sputum eosinophilia was tested, and the prevalence and significance of this finding was studied.