The conventional Pap smear method, with many studies showing that 80% of cells are discarded after smearing on the slide, increases the rate of missing abnormal cells. In addition, with the conventional Pap smear method, cells are not well preserved and the observed sample has a lot of mucus. The smear often has errors of thick smears, cells overlap each other. To overcome these limitations, in 1996 the US Food and Drug Administration (FDA) recognized the Liquid-based cytology (Thinprep) method as a method in cervical cancer screening.