The PAPNET system for quality control of cervical smears: validation and limits

The Pap-test may fail to identify false negative cases. Probably only full rescreening assisted by instrument can prevent potential screening and interpretation errors. Therefore, the PAPNET System was used obtain accurate Quality Control (QC) of 3000 conventional cervical smears. Sixteen false negatives were detected with the rescreening assisted by PAPNET. Thirteen positive cases were suspected during evaluation assisted by the PAPNET; two cases were classified as Review for potential inflammatory cellular changes and underwent full optic microscope. In one case both primary screening and the PAPNET did not detect the only abnormal cell cluster located near the coverslip edge, being part of the slide excluded from the scanning process due to focusing problems: only coverslip edge rescreening by optic microscopy allowed the formulation of the correct conclusive diagnosis. In conclusion, the PAPNET System is useful for QC of conventional cervical smears: in fact this instrument allows the identification of false negative cytological errors easily and effectively. Nevertheless, some slide scanning program modifications are needed to detect all abnormal cells present on slide under coverslip.