title: Quality assurance in cytology. Rescreening of previously negative smears from high grade squamous intraepithelial lesions.
abstract: OBJECTIVE
  To determine the problem areas in the cytologic diagnosis of high grade squamous intraepithelial lesion (HSIL) (cervical intraepithelial neoplasia [CIN] 3).
  
  
  METHODS
  Previously negative smears from cases with histologically proven CIN 3 in 1988 and 1992 were reviewed for any discrepancies between the original and reviewed diagnoses. Such features as the presence of excessive inflammation, blood or bacteria, and atypical and dysplastic cellular changes were assessed. Original and reviewed reports for both years were compared, and the false negative rate was calculated.
  
  
  RESULTS
  In the 1992 study, small numbers of abnormal cells, abnormal cells masked by inflammation and pale-staining HSIL were the common patterns when the diagnosis of HSIL was initially overlooked. In the 1988 study, the abnormal cells were overlooked mainly because of suboptimal smears.
  
  
  CONCLUSIONS
  Determining cytologic patterns that pose problems in the diagnosis of HSIL is a valuable quality assurance procedure used in our laboratory. In performing these studies, we are able to pinpoint problem areas and educate our staff so as to minimize the number of false negative smears.
authors.affiliation: Institute of Clinical Pathology and Medical Research, Westmead Hospital, Sydney, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Howell
authors.forename: M
authors.initials: M
authors.lastname: Theodor
authors.forename: N F
authors.initials: NF
authors.lastname: Pacey
authors.forename: J R
authors.initials: JR
authors.lastname: Patwardhan
authors.forename: B
authors.initials: B
authors.lastname: Ayer
mesh_terms: D003585:Cell Biology / Q000592:standards*; D003951:Diagnostic Errors; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D011786:Quality Control; D015203:Reproducibility of Results; D002583:Uterine Cervical Neoplasms / Q000473:pathology*; D002578:Uterine Cervical Dysplasia / Q000473:pathology*