Improvement in the routine screening of cervical smears: A study using rapid prescreening and 100% rapid review as internal quality control methods.

Background: High rates of false-negative results constitute a routine problem in cytology laboratories. Of currently available internal quality control methods, 10% random review is the least effective in detecting false-negatives in routine screening. There is evidence that 100% rapid review and rapid prescreening perform well for this purpose. This study compared the performance of rapid prescreening and 100% rapid review as internal quality control methods for cervical cytology exams.

Methods: Over 27 months, 12,208 cervical cytology smears were submitted to rapid prescreening and routine screening. The 100% rapid review method was performed on all smears classified as negative or unsatisfactory at routine screening. Conflicting results obtained with either method were reviewed in detail to define final diagnosis, which was considered the gold standard for evaluating the performance of rapid prescreening and 100% rapid review.

Results: Compared with final diagnosis, the sensitivity of routine screening and rapid prescreening was 72.9% and 75.6%, respectively. Considering only smears classified as negative or unsatisfactory at routine screening, the sensitivity of rapid prescreening and 100% rapid review was 90.2% and 57,0%, respectively. Of 244 cases (2.0%) of false-negative results at routine screening, rapid prescreening identified 220 cases (1.80%), whereas 100% rapid review identified 140 (1.15%). Rapid prescreening detected all cases of HSIL identified as false-negatives.

Conclusions: Rapid prescreening is more effective than 100% rapid review for the detection of false-negatives at routine screening, thus providing subsidies for the performance of cervical cytology, the principal function of which is to detect precursor lesions of cervical cancer.