FLOW CYTOMETRY OF HUMAN GYNECOLOGIC SPECIMENS USING LOG CHROMOMYCIN A3 FLUORESCENCE AND LOG 90-DEGREES LIGHT SCATTER

Flow cytometry and electronic cell sorting are being investigated to screen gynecologic specimens for cervical neoplasia. Cellular DNA content is quantitated by Chromomycin A3 fluorescence and cell size is quantitated by 90° light scatter; the logarithms of the measured intensities are used to produce a two parameter histogram. To determine the cell types responsible for signals in various histogram regions, systematic electronic cell sorting is performed. The sorted fractions are sedimented onto microscope slides and stained by the Papanicolaou technique. The cells in each fraction are identified by conventional cytomorphologic criteria. Morphologic analysis of sorted cells reveals histogram regions corresponding to specific cell types. One very important region contains the highest concentration of signals from abnormal cells and is therefore the best region to analyze for specimen abnormality. However, because a significant number of signals in this region are from normal cells, specimens cannot be diagnosed by their analysis. Another important histogram region is composed primarily of signals from endocervical columnar and metaplastic cells. The presence of such cells is a good criterion for specimen adequacy, therefore analysis of signals in this region is essential to assess specimen adequacy for automatic screening.