Using the Pathfinder system to reduce missed abnormal cervical cytologic smear cases in a rescreening program.

OBJECTIVE

To evaluate the effect of Pathfinder (CompuCyte Corp., Cambridge, Massachusetts, U.S.A.), a process control instrument for microscopes used by cytotechnologists to monitor the mechanical aspects of their screening process, on the false negative cervical cytologic smear rate as detected in daily quality assurance rescreening.

STUDY

DESIGN

Pathfinder was put into routine use in a large cytology laboratory. After cytotechnologists were trained in its use, they monitored their time spent screening each slide, the area (percent) of the slide screened and the average percentage of overlap of fields of view. The number of abnormal cases missed in screening before and after the introduction of Pathfinder was determined by rescreening a random 10% of the "negative" cases. The evaluation took place over a nine-month period.

RESULTS

A decrease in the number of missed abnormal cases was identified. The false negative rate for atypical cells of undetermined significance (ASCUS) fell from 37/2,336 (1.6%) to 12/1,772 (0.7%), for a 56% decrease. The change in the number of squamous intraepithelial lesion cases, even over a nine-month period, was too small for comment.

CONCLUSION

The effect of the continuous feedback and process standardization provided by the Pathfinder system was a decrease in the number of abnormal cases missed. This was due primarily to a marked decrease in the number of ASCUS cases missed. The Pathfinder provides a number of innovative management tools to ensure consistent high quality screening.