Improvement of the preparation method for vaginal smears for the auto-cyto-screener.

An improved method of preparing vaginal smears for use in the Auto-Cyto-Screener is reported. The main alterations from the previous technique were the substitution of 2% formaldehyde phosphate buffer (pH 7.4) for 50% ethanol as the preservative fluid, the use of homogenization in place of sonication for cell aggregate dispersion and the introduction of Ficoll-gradient sedimentation, which not only removes leukocytes and other elements from the suspensions but also concentrates the cancer cells to some extent. An examination of cell deposition techniques showed that optimal results were achieved with the use of filter paper, not rubber, and with centrifugation performed immediately after loading the suspension into the chambers.