A Pap smear (also known as the Pap test) is a medical procedure in which a sample of cells from a woman's cervix (the end of the uterus that extends into the vagina) is collected and spread (smeared) on a microscope slide. The cells are examined under a microscope in order to look for pre-malignant (before-cancer) or malignant (cancer) changes.
A Pap smear is a simple, quick, and painless screening test. Its specificity - which means its ability to avoid classifying a normal smear as abnormal -- while very good, is not perfect. The sensitivity of a Pap smear - which means its ability to detect every single abnormality -- while extremely good, is also not perfect. Thus, a few women develop cervical cancer despite having regular Pap screening.
In most cases, a Pap test does identify minor cellular abnormalities before they have had a chance to become malignant and at a point when the condition is most easily treatable. The Pap smear is not intended to detect other forms of cancer such as those of the ovary, vagina, or uterus. Cancer of these organs may be discovered during the course of the gynecologic (pelvic) exam, which usually is done at the same time as the Pap smear.
In a pelvic exam, a speculum (an instrument for opening and widening certain passages of the body) is used to open the vagina and aid in visualizing the uterine cervix. A sample of cells may be taken off the surface of the cervix for a Pap smear or a sample may be obtained for laboratory culture. The uterus womb and ovaries are felt with the fingers to detect swellings or other abnormalities. the Pap smear.