Improved Accuracy for Cervical Cytology with the ThinPrep Method and the Endocervical Brush-Spatula Collection Procedure

OBJECTIVE: Our objective was to assess the sensitivity of a fluid-based, thin-layer slide preparation system (ThinPrep; Cytyc Corporation, Boxborough, MA), as compared to conventional Papanicolaou smears obtained with the endocervical brush and spatula sampling devices. PATIENTS AND METHODS: Two groups totaling 1,583 patients, all of whom were attending Planned Parenthood of the Rocky Mountains clinics, were included in the study. Cervical cell samples taken with the endocervical brush and plastic spatula were used first to make a conventional smear. Then the residual cells were rinsed into a vial containing preservative fluid, from which a ThinPrep slide was made. Screening and diagnosis of ThinPrep and conventional slides were blinded. RESULTS: The ThinPrep method demonstrated 110% greater detection of low-grade squamous intraepithelial lesions and more severe diagnoses as compared to the conventional smear. The ThinPrep method yielded 54% more high-grade squamous intraepithelial lesions than did the conventional smears. Review by an independent pathologist confirmed the significant increase in detection of low-grade squamous intraepithelial lesions and more severe diagnoses. CONCLUSION: The data from more than 1,500 patients indicate improved sensitivity for the detection of disease with the ThinPrep cervical slide preparation method.