The cytobrush for evaluating routine cervicovaginal-endocervical smears. While the conventional wooden spatula/cotton-tipped applicator has remained the method of obtaining Papanicolaou smears for most clinicians at the University of California at Los Angeles, the Student Health Service (SHS) adopted the Zelsmyr cytobrush as its sole method of obtaining cervical samples in late 1986. A study was done to define changes in both the adequacy of sampling and the detection rate for both squamous and glandular epithelial abnormalities with the cytobrush. To accomplish this goal, 1,000 cytobrush and 244 conventionally obtained smears were analyzed prospectively, and 3,864 SHS samples obtained in 1986 prior to the change in method were reviewed retrospectively. As compared to cervical samples obtained by conventional methods, the cytobrush smears contained significantly more endocervical cells and had fewer drying artifacts. Both methods obtained equivalent squamous samples and had similar final class distributions. No case of endocervical adenocarcinoma carcinoma in situ or invasive adenocarcinoma was detected. SHS patients who had initial "no endocervical cells" samples but whose repeat sample did contain endocervical cells retained the same class in more than 75% of cases. This study confirmed that the cytobrush technique produces Papanicolaou smears with improved sampling of the squamocolumnar junction but questioned whether that results in an increased detection rate for cervical pathology. 