Improving the yield of direct chorionic villus slide preparations.

Low cytogenetic yields in the processing of small chorionic villus sampling have in some instances, limited its applicability. We have modified "standard" techniques to increase the number of interpretable metaphases by (1) using a gravity method for cell suspension spreading and (2) using a special high-quality slide glass. Both modifications reduce cell damage and increase interpretable mitotic figures and may allow a cytogenetic diagnosis in some instances in which a diagnosis might not otherwise be possible with standard methods.