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Diagnostic reproducibility and accuracy in evaluating cervical/vaginal smears were the focus of this study concerning intralaboratory quality control. A set of 120 cytological samples was evaluated by 15 cytopathologists whose experience ranged from 3-29 yr. The study report form was based on the 1988 Bethesda System. Intercytologist reproducibility (with respect to sample adequacy, epithelial cell abnormalities, and presence of cellular changes associated with HPV, Human Papilloma virus) was evaluated using the Kappa statistic. Poor reproducibility in defining sample adequacy was observed (K = 0.24). The agreement on epithelial cell abnormality definition was good (K = 0.64); the lowest reproducibility was observed for High-grade squamous intraepithelial lesion/cervical intraepithelial neoplasia HSIL/CIN II (specific K = 0.37) and Atypical cells of undetermined significance ACUS (specific K = 0.44). The agreement in detecting cellular changes associated with HPV was fair (K = 0.49). Diagnostic accuracy for epithelial cell abnormalities, assessed by comparison with a consensus reference diagnosis, was good (K = 0.74).

A set of 300 vaginal smears was interpreted by 13 cytologists from six European laboratories, who were requested to report inadequate and suboptimal smears. The set had been appropriately seeded to reach approximately 10% inadequate and 20% suboptimal smear frequency. According to the majority report, 230 smears were classified as adequate (76.7%), 43 as inadequate (14.3%), and 27 as suboptimal (9.0%). Agreement with the majority report ranged from 52% to 91% (average 78%). Kappa statistics for reporting inadequate smears showed a high level of agreement for five cytologists, and fair to good agreement for eight. In contrast, kappa statistics for reporting suboptimal smears showed fair to good agreement with the majority report only in five instances, whereas agreement was poor for eight cytologists. 'Inadequate smear' rates may be used to compare the quality of smears received in different laboratories, as there is a high level of agreement among cytologists as to what constitutes an inadequate smear. However, this is not true for "suboptimal smear" rates, and more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears: more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears.

Objective: To evaluate the diagnostic agreement between seven cervical/vaginal cytology laboratories participating in the first external quality assurance (EQA) scheme developed in Italy., Study Design: Between 1991 and 1993, 110 cytologic smears were selected and classified by a committee and circulated and reported on by the laboratories according to the 1988 Bethesda System. Agreement was evaluated with the kappa statistic. Systematic disagreement was assessed by means of the Wilcoxon signed rank test., Results: Interlaboratory kappa values varied between .01 and .29 (group score, .11) for sample adequacy and between .53 and .78 (group score, .67) for epithelial abnormalities. The lowest specific kappa values were observed for the three classes of sample adequacy (unsatisfactory, .07; less than optimal [LTO], .10; satisfactory [SAT], .14) and for the class of atypical cells of undetermined significance (ACUS), (.29). As compared with the study committee, 5/7 laboratories showed a systematic (P<.01) tendency to undercall sample adequacy. Agreement on epithelial abnormalities was also analyzed according to the pattern of adequacy reported by paired laboratories (LTO/LTO, LTO/SAT, SAT/SAT). As compared with smears designated SAT/SAT, those classified as LTO/SAT were associated with lower specific kappa values for agreement on the presence of carcinoma and ACUS and with equal or greater values for agreement on the other classes, suggesting an arbitrary use of notations of LTO inversely related to the severity of epithelial lesions., Conclusion: EQA schemes, as applied to cervical/vaginal cytology, can shed light on major deficiencies in specific diagnostic areas.