Pap Smear Collection and Preparation: Key Points

Cytology is the science of study of cells. It is derived from the Greek word "cytos" which means cells. The cells of the cervicovaginal epithelium are continuously evolving. The mature cells reach the surface and are then exfoliated. Initially, these exfoliated cells were collected from the posterior fornix, which showed cells from endocervix, ectocervix, and the vaginal epithelium. Hence, it was known as the exfoliative vaginal cytology. But now, the cells are taken directly by scraping the ecto and the endocervix. A variety of sampling devices are available in the market. The basic aim is to augment sampling of the complete transformation zone (TZ) as well as the squamocolumnar junction (SCJ) and cause least possible trauma to the cervical and endocervical epithelium during its use. The SCJ is of crucial significance for cervical cancer pathogenesis. Most of the precancerous changes take place within the TZ and at the SCJ. Hence, the collection of cells from this area is of utmost importance. The reliability of cervical cytology for the detection of precancerous lesions also strongly depends on immediate wet fixation of the smear. Therefore, the gynecologists or the paramedics who perform the conventional Pap smears must not only be trained in the art of cell collection and smearing of the material onto the glass slides but also learn immediate wet fixation of the cervical cells. Liquid-based preparations have made all these steps relatively easy for them as the design of the Cervex brush is such that it mostly ensures the sampling of the complete TZ and the SCJ. Pre-fixation of cells occurs in the vial containing a weak fixative and the transfer of cells onto the glass slide is standardized by the automated stations designed for this purpose. This chapter gives an in depth description of the prerequisites and precautions while collecting and preparing a Pap smear with different devices, especially for settings where conventional smears are still the norm. Instructions for women undergoing Pap smear and the medical personnel who conduct this test are also highlighted.