Reliability of a quantitative interpretation of sputum cytology slides

A sputum cytology method has been developed in which eight cytologic components associated with stimulation of the bronchial airways are quantified. The extent to which cytotechnologists could reliably and consistently utilize this system was measured. In an initial study (study A), four cytotechnologists had an overall intraobserver agreement of 90.2% and an interobserver agreement of 76.3%. There was an overall agreement with the laboratory standard of 85.6%. The most difficult components to consistently rate were mucous spirals and metaplastic, dysplastic and columnar cells. Study B was initiated after the implementation of a training program designed to better define both cytologic criteria and our system of quantitation. Two of the original cytotechnologists and a newly trained cytotechnologist participated in study B. The overall intraobserver agreement increased to 97.8% while the overall interobserver agreement increased to 97.5%. The overall agreement with the laboratory standard was 98.3%. These results indicate that a cytologic rating system employed for quantitative sputum cytology can be taught and applied reliably and consistently.