Rescreening in gynecologic cytology. Rescreening of 8096 previous cases for current low-grade and indeterminate-grade squamous intraepithelial lesion diagnoses--a College of American Pathologists Q-Probes study of 323 laboratories.

Abstract

To quantitate, characterize, and analyze errors identified in the rescreening of previous gynecologic cytology specimens with original diagnoses of within normal limits or benign cellular changes for current cases diagnosed as low-grade squamous intraepithelial lesion or squamous intraepithelial lesion of indeterminate grade. College of American Pathologists Q-Probes laboratory quality improvement study in 323 laboratories. False-negative rate in cases rescreened as a result of a current cytologic diagnosis of low-grade squamous intraepithelial lesion or squamous intraepithelial lesion of indeterminate grade. A total of 8096 smears performed within the 5 years preceding the current examination were rescreened. Of the rescreened cases, 284 (3.5%) were reclassified as a squamous intraepithelial lesion or carcinoma, 474 (5.9%) as atypical squamous cells of uncertain significance, 7 (0.09%) as atypical glandular cells of uncertain significance or glandular intraepithelial lesion, and 39 (0.5%) as unsatisfactory. Ninety-three percent (261/280) of all false-negative cases were identified in cases from the previous 3 years. Rescreening archival cytology cases previously diagnosed as within normal limits or benign cellular changes for current cases diagnosed as low-grade squamous intraepithelial lesion or squamous intraepithelial lesion of indeterminate grade will identify screening and diagnostic errors. This may be a useful quality improvement monitor in many laboratories.