Cytology screening

The cervical cancer screening programme aims to detect Cervical intraepithelial neoplasia (CIN). CIN, also known as cervical dysplasia, is the abnormal growth of cells on the surface of the cervix that could potentially lead to cervical cancer. Screening aims to prevent cervical cancer by treating high-grade CIN (i.e. CIN2 and CIN3).

Currently (until January 2020) screening for cervical cancer in England is done through the collection, staining, and microscopic examination of cells from the cervix. The stain used to assess collected cells was developed by George Papanicolaou in the early 1940s and is usually referred to as the Papanicolaou (or pap) test. Originally the pap test was done by collecting cells from the cervix using a spatula or a brush and smearing them onto a glass slide (known as conventional cytology) before staining. More recently liquid based cytology (where the cells are deposited directly into a small glass pot containing preservative fluid before being transferred onto a glass slide) has been favoured as it leads to lower rates of inadequate samples. Importantly the cells collected using liquid based cytology (LBC) can be tested for the presence of the HPV virus.