Statistical quality assurance in cytology : use of the Pathfinder to continuously assess screener process control in real time

To evaluate the suitability of the Pathfinder (CompuCyte Corp., Cambridge, Massachusetts, U.S.A.), an innovative instrument for monitoring the mechanical aspects of cytology screening, as a training aid and workstation component for cytotechnologists for daily work flow in a large cytology laboratory. The impact of the implementation of the Pathfinder was assessed by comparing the performance of a group of senior cytotechnologists with the Pathfinder features enabled (displayed) and disabled (not displayed). When enabled, statistical parameters, including the percentage of screenable slide surface viewed, the amount of time spent viewing the slide and the percentage of overlap of the fields of view, were continuously displayed to the cytotechnologist on a small, dedicated video display terminal. Areas of the slide requiring additional review by the pathologist were indicated by a series of electronic icons placed by the cytotechnologists. The Pathfinder was found to provide critical insight into the variability that exists among cytotechnologists in their approach to screening. By establishing laboratory performance criteria for the aforementioned parameters, variability in performance could be reduced immediately. The continuous feedback provided by the Pathfinder to the cytotechnologist during the actual screening process could help to diminish false negative cervical cytologic smear evaluations due to correctable unsuspected errors in the practice of screening.