Interlaboratory quality assurance in cervical/vaginal cytology

V. Cocchi, C. Sintoni, D. Carretti, D. Sama, U. Chiari, A. L. Delazer, N. Grilli, R. Papaleo, C. Ghirardini, L. Bucchi

Research output: Contribution to journalArticlepeer-review


Ultimate aim of external (interlaboratory) quality assurance (EQA) in cervical/vaginal cytology practice is to achieve adequate levels of diagnostic reproducibility and accuracy. Basic EQA models include slide exchange schemes and proficiency testing programmes. Available studies (from USA, Canada, and UK) differ in management, objective, design, size, end points, and analysis, and suffer from specific biases. However, EQA provides information not otherwise available and is an essential component of the monitoring of cervical screening. In Italy an EQA pilot study was carried out in the Emilia-Romagna Region. Between 1991 and 1993, 110 pap smears were selected by a Committee and independently reported by the seven laboratories according to the 1988 Bethesda System. Interlaboratory reproducibility of sample adequacy classification was unacceptably poor (κ range, 0.01-0.29; total 0.11). Compared with the study Committee, 5/7 laboratories showed a significant tendency to underestimate sample adequacy. Fair to good κ scores were observed for interlaboratory agreement on cytology diagnosis (κ range, 0.53-0.78; total 0.67). The lowest specific κ values were observed for the three classes of sample adequacy (UNS 0.07, LTO 0.10, SAT 0.14) and for the class of ACUS (0.29). Cytohistologic correlations showed that the consistency of cytology reports with original final diagnoses, as evaluated with the κ index for comparison purposes, was slightly lower (κ=0.50) than interlaboratory agreement. The highest predictive value was that of the cytology reports of G-ACUS for the diagnosis of AdCA (85%).

Original languageEnglish
Pages (from-to)149-156
Number of pages8
JournalMedecine Biologie Environment
Issue number2
Publication statusPublished - 1995


  • Accuracy
  • Cervical cancer
  • Cervical/vaginal cytology
  • Consistency
  • Mass screening
  • Quality assurance
  • Reproducibility

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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