The Papanicolaou test ( Pap test) is a screening test used to detect potentially pre-cancerous and cancerous processes in the endocervical canal  (transformation zone) of the female reproductive system. Unusual findings    

are often followed up by more sensitive diagnostic procedures, and, if warranted, interventions that aim to prevent progression to cervical cancer.
It is recommended that females who have had sex seek regular Pap smear testing In taking a Pap smear, a speculum is used to open the vaginal canal and allow the collection of cells from the outer opening of the cervix of the uterus and the endocervix. The cells are examined under a microscope to look for abnormalities. The test aims to detect potentially pre-cancerous changes (called cervical intraepithelial neoplasia (CIN) or cervical dysplasia), which are usually caused by sexually transmitted human papillomaviruses. The test remains an effective, widely used method for early detection of pre-cancer and cervical cancer. The test may also detect infections and abnormalities in the endocervix and endometrium.