Characterizing the Effect of Automated Cell Sorting Solutions on Cytomorphological Changes

Introduction: Liquid-based cytology has become a widely adopted, automated screening system for gynecologic and nongynecologic cytology. Automated screening systems function by distinguishing atypical cells based on their cytoplasmic and nuclear areas, densitometric measurement, and so on. However, the morphological influence of the washing solution has not been fully considered. Here, we examined the morphological effect and temporal change resulting from saving the cytologic samples in various solutions. Methods: Cytologic specimens were obtained from the ascites (AS) of patients with peritoneal cancer. Various solutions of a physiological saline, a Ringer’s solution, a low-molecular dextran L injection, VOLUVEN 6% solution, MIXID L injection (ML), RPMI-1640 medium, and horse serum (HS) were added to aliquot sediments. All samples were refrigerated at 4°C, and aliquots were subsequently processed at specific time points (0, 1, 2, 4, 7, and 14 days). For all samples, cytoplasmic and nuclear size of the Papanicolaou-stained specimens were measured. Results: In terms of cytoplasmic and nuclear areas, samples stored in ML and HS showed no significant difference compared to the AS sample; in contrast, the other samples were significantly larger in both cytoplasmic and nuclear areas than the AS sample. In examining the temporal change among the solutions, we found that the cytoplasms and nuclei became small over the time course for all of the tested solutions. Conclusion: We showed that cells swell in the solution after 1 h of storage and contract as time progresses. Together, our findings have important implications for how mathematical analysis is applied during the automated screening process.