What is a pap test?

Indications and Procedures

Pap testing guidelines have recently changed. Formerly, the procedure was recommended for all women over the age of eighteen or for women who are sexually active. Revised guidelines have been issued by the American Cancer Society, the American College of Obstetricians and Gynecologists, and the Preventive Services Task Force, part of the US Department of Health and Human Services. These updated guidelines all stipulate that Pap tests should begin in women aged twenty-one and older. Updated guidelines have been issued as well for Human papillomavirus (HPV) testing, which frequently accompanies the procedure; it is now recommended that HPV testing be done in women aged thirty and older because HPV in younger women is usually a transient infection that will clear without need for intervention.

The guidelines also recommend less frequent Pap testing for women who have had three consecutive negative tests; the guidelines also call for a cutoff to Pap testing in older women without abnormalities. Pap testing guidelines for women who have had a hysterectomy (with sampling of the vaginal cuff) vary depending on whether the hysterectomy was done for benign or malignant causes. The guidelines recommend that only women who have had malignant disease continue Pap testing.

A Pap test is performed easily in an office visit. Generally, the patient lies on her back with legs flexed and knees apart, although alternative positions can be utilized for women with limited mobility or with disabilities. A speculum is then carefully inserted into the vagina, and the cervix is visualized. A spatula is used to gently scrape off cells from the transition zone of the cervix. A cytobrush samples cells from the cervical canal. These cells are then placed in a preservative and sent to a pathology laboratory for analysis. The term “Pap smear” derives from the fact that before the advent of liquid preservative methods of collecting samples, samples were “smeared” on a glass slide and then sent to a laboratory for analysis.

Uses and Complications

The main use of Pap testing is to identify asymptomatic cases of dysplasia (abnormal growth) of the cervix and vagina. With early treatment of dysplasia, the incidence of and number of deaths from cervical cancer
have decreased dramatically. Although cancer screening is the primary purpose and use of Pap testing, incidental findings may include vaginal infections of bacteria, fungi, or parasites. In rare cases, Pap tests may also detect abnormal cells shed from the endometrium.

There are no serious risks from the procedure. Women may see a small amount of spotting after the procedure as a result of abrasions from the spatula or cytobrush.

Perspective and Prospects

The Pap test was introduced in 1943 by George N. Papanicolaou and Herbert F. Traut. Since then, the incidence of invasive cervical cancer has dramatically, although cervical cancer remains the second most prevalent malignancy among women worldwide, according to the World Health Organization.

A screening test analogous to cervical Pap sampling, called the anal cytology, or "anal Pap test," has been developed to screen for anal dysplasia and cancer. It has been used primarily on high-risk patients, such as those with Human immunodeficiency virus (HIV), women who have had cervical or vulvar cancer, and HIV-negative men who have sex with men.

Bibliography

A.D.A.M. Medical Encyclopedia. "Pap Smear." MedlinePlus, February 26, 2012.

"Cervical Cancer Screening." Centers for Disease Control and Prevention, June 13, 2013.

Kumar, Vinay, et al., eds. Robbins Basic Pathology. 9th ed. Philadelphia: Saunders/Elsevier, 2013.

Lentz, Gretchen M., et al. Comprehensive Gynecology. 6th ed. Philadelphia: Mosby/Elsevier, 2012.

National Cancer Institute. "Cervical Cancer Screening." National Institutes of Health, US Department of Health and Human Services, July 19, 2012.

"Pap Test." Health Library, March 15, 2013.

Wright, Thomas C., Jr., et al. “2001 Consensus Guidelines for the Management of Women with Cervical Cytological Abnormalities.” Journal of the American Medical Association 287, no. 16 (April, 2002): 2120–2129.