Modified Drop Technique: Preparation of Smears for Automatic, Electronic Scanning

Abstract

A modified application of the “drop technique” for cytology and its desirability for automatic, electronic scanning are discussed. Vaginal pool aspirates like all cytological specimens frequently have sparsely populated cellular material, and when the Cytoanalyzer is used, an optimum sampling of well-prepared specimens is desirable. Specimens are obtained by aspiration from the posterior vaginal fornix and suspended in 75 percent ethanol for fixation. This suspension is poured through a fine sieve and centrifuged; the supernatant is removed, the cellular material is diluted to a known density, and a known quantity of the specimen is dropped on a slide and spread over a previously defined area with the tip of the pipette. Feulgen staining is used to obtain a nuclear stain of medium intensity with minimal staining of the cytoplasm. A coverslip is mounted with Permount and the slide is ready for automatic scanning. Processing by this method provides an adequate control of the number, spacing, and distribution of cells in the smear without distorting their morphological characteristics.