False negative rate in quality assessment of pap smears - Rescreening from522 histologically proven lesions

Determining the false negative rate of cervical smear interpretation is an important part of quality assessment and a necessary step for any improveme nt program. We report our experience of negative smear rescreening of 522 h istologically proven high-grade lesions or cancers, over a 5 to 7 year prec eding period. False negative rate was 6:88 % as calculated with a narrow de finition of error, i.e. intra-epithelial lesions and atypical squamous cell s of untermined significance. It was 10.78 % as calculated with a broad def inition of error, including minor anomalies such as repair and parakeratosi s. Bibliographic data account for 0 to 94 % false negative diagnoses, owing to great disparities in calculating the false negative rate as well as in rescreening. However, a 10 % traditionally calculated and standardised fals e negative rate is a reasonable and achievable goal in a view of quality im provement. Systematic random rescreening of 10 % of negative smears is inef fective.