Has the ThinPrep method of cervical screening maintained its improvement over conventional smears in terms of specimen adequacy?

Abstract

Liquid-based cytology (LBC) has replaced conventional smear assessment in many centers over recent years. In our laboratory this transfer took place in 1999. At that time we performed a split sample study comparing the conventional method of cervical smear evaluation with the ThinPrep system. This split sample study identified a dramatic improvement in specimen adequacy with LBC. While 11% of conventional preparations were reported as unsatisfactory and almost 9% were reported as suboptimal, evaluation of the same cases using LBC saw this combined figure reduced to 2.3%. To evaluate whether this dramatic fall in unsatisfactory smears has been maintained with the use of LBC. The database for all smears reported for 2005 (100% LBC) was interrogated. The number of unsatisfactory reports was calculated. The reason for an unsatisfactory report was recorded for each case. The overall unsatisfactory rate was compared with that reported in the 1999 split sample study. A total of 41,312 smear tests were reported in 2005. 1,342 (3.25%) were reported as unsatisfactory. Our findings support the ongoing value of LBC in a routine cervical screening laboratory in terms of continuing to maintain a low rate of unsatisfactory smears.