[Determination of a significant cell count for positive diagnosis in gynecologic suspension preparations and possible consequences for the analysis of automated preparations].

Monolayer preparations used in automated cytology are generated from gynecologic cell suspensions. The suspension-derived preparations (s.p.) show some peculiarities compared with conventional cytologic smears. One important feature of the s.p. is a distribution of cells mainly by chance. Therefore it seems to be possible to determine a cell sample size in minimum needed for cytologic diagnosis. In a blind test the needed cell sample size was determined by counting the cells in the microscopic fields of vision (ocular 12,5 x, objective 10 x, phi of the field of vision 2 mm) step by step until it was possible to classify the specimen (diagnosis 1). To be on the safe side (personal safety requirement) some further cells were assessed (diagnosis 2). We used s.p. from 50 non-suspicious women and 50 women with invasive squamous cell carcinoma of the uterine cervix and its precursors. To recognize strong positive cases (severe dysplasia to invasive carcinoma) only about 600 cells are needed (mean: 150/147 cells). The most cells (about 1200 cells) are required in negative cases and cases of mild to moderate dysplasia (mean: 293/236 cells). The highest personal safety requirement was found in cases of mild to moderate dysplasia (311% compared with a mean sample size of 236 or 100%). The results support such approaches in automated cytology which analyze only some hundreds or about 1000 cells with high resolution.