Prospective study of concurrent ploidy analysis and routine cytopathology in body cavity fluids.

A total of 390 body cavity fluids were analyzed by both cytopathologic examination and flow cytometric DNA analysis. The two methods gave compatible results in analyses of 304 fluids (78%). In 24 patients, cytopathologic studies found the specimens to contain malignant cells, but the DNA content was diploid. This illustrates an area where flow cytometric studies do not extend tumor detection. In 56 fluids from 48 patients, cytologic methods revealed no malignant cells but flow cytometry distinguished aneuploid cell populations; additional clinical information allowed the identification of malignant tumors in 24 (50%) of these patients. Because flow cytometry was able to detect aneuploidy in cases where conventional cytologic examination could not detect malignant cells, the number of patients with tumors detected was increased by 39% beyond those detected by cytologic methods alone in this series.