Evaluation of two simultaneously obtained cervical cytological smears.

Abstract

The cytological readings were evaluated of 2 simultaneously obtained cervical Pap smears from a cohort of 30000 women. The distribution of diagnostic categories among central and periopheral laboratories was closely similar. In 32 cases diagnosed on the first slide as severe dysplasia-carcinoma in situ only 2 cases were confirmed on the second slide and 12 negative readings were reported. In 21 cases diagnosed on the second slide as severe dysplasia-carcinoma in situ only 2 cases were confirmed on the first slide and 7 negative readings were reported. Negative findings occurred in about 1/3 of first and second slides. In only 29 of 211 cases or mild or moderate dysplasia was the diagnosis the same for both slides. Reexamination of variant paired slides resulted in few diagnostic changes. The different diagnoses are attributed to differences in the cell material rather than to interpretation possibly as a result of the method for obtaining cell material. Thus representative cells were absent in about 33% of the cases of carcinoma in situ and in 50% of the cases of mild-to-moderate dysplasia. It was concluded that the prevalence of false negative readings in actual practice is higher than generally believed and that the taking of 2 smears simultaneously may increase the chance of positive readings by 50%.