Utility of additional slides from residual Preservcyt material in difficult ThinPrep gynecologic specimens: a prospective study of 58 cases.

ThinPrep purportedly increases the sensitivity of cervicovaginal cytology for detecting abnormal squamous and glandular cells. The value of additional slides from residual Preservcyt material to characterize difficult lesions is unknown. Fifty-eight cases were studied to determine the utility of additional slides for diagnosis and to assess cellular uniformity. In 32 (55%), repeat slides helped make a definitive diagnosis, including 18 atypical squamous cells of uncertain significance (ASCUS) reclassified as low-grade squamous intraepithelial lesion (LGSIL) (13), high-grade squamous intraepithelial lesion (HGSIL) (4), or endometrial adenocarcinoma (1); 5 LGSIL reclassified as HGSIL; 3 atypical glandular cells of uncertain significance (AGUS) reclassified as LGSIL (1) or HGSIL (2); 2 LGSIL?HGSIL classified as LGSIL; and 4 cases confirmed as LGSIL (2) or HGSIL (2). Results were compared to follow-up clinical information, including subsequent cervicovaginal samples and biopsies. The number of abnormal cells was similar between slides in most cases. We conclude that, while ThinPreps prepared from the same vial have similar numbers of abnormal cells, additional slides can be helpful for diagnosis in select cases.