Although the Pap smear may be done as part of the evaluation of a symptomatic woman, it is usually collected for screening purposes.

The various organizations for disease prevention and health promotion disagree on how frequently women should have Pap smear screening and at what ages screening should begin and end. The rationale for different recommendations may be found in the background section. The guidelines of the American College of Physicians (ACP), the United States Preventive Services Task Force (USPSTF), the Canadian Task Force on the Periodic Health Examination (CTF), and others are summarized in the following table. The major difference among them is the recommended screening interval after age 35. Click on the organization names for more information about each guideline.

Women at higher risk for cervical cancer
The recommendations for women who are at higher risk for cervical cancer are controversial. Risk factors include young age at first intercourse, smoking, use of oral contraceptives (Eddy, Kjaer), multiparity (Miller), human papilloma virus (Lieu), low socioeconomic status (Brinton), HIV infection (Hankins), advancing age, high lifetime number of male sexual partners, promiscuity of the sexual partner, and having a sexual partner with penile cancer (Lichtman). Certain ethnic groups, particularly blacks, Hispanics, and Native Americans, have higher rates of cervical cancer (Eddy). Women who do not receive regular Pap testing are also at higher risk for cervical cancer. Incomplete Pap testing is more common among blacks, the poor, the uninsured, the elderly, and those living in rural areas (USPSTF). Some groups, such as the Canadian Task Force, propose incorporating risk factors into recommendations for screening frequency. Thus far, there are no recommended guidelines for screening such women.

Women who have had a hysterectomy
The Pap screening recommendations for women who have had a hysterectomy differ from the recommendations for women with an intact cervix.

The 1996 U.S. Preventive Services Task Force recommends Pap testing after hysterectomy if:

• The cervix was left behind at surgery
• The hysterectomy was performed because of cervical cancer

The Canadian Task Force suggests NO screening post-hysterectomy if:

• The hysterectomy was for a benign condition, AND
• There was pathologic documentation that the cervical epithelium had been completely removed, AND
• Smears before surgery were normal (Miller).

"No widely accepted Pap smear screening protocol after hysterectomy has been formulated, and the effectiveness of Pap smear screening for vaginal cancer is not well-substantiated" (McIntosh). Pearce reported that "the prevalence of abnormal findings on cytopathological examination of vaginal Papanicolaou smears after hysterectomy for benign gynecologic disease is extremely low" (Pearce). It may therefor, be more valuable to identify women who are at higher risk for vaginal cancer. A history of previous abnormal Pap smear of either the cervix or vagina places women in a higher risk group (McIntosh). Women who still have a cervix certainly warrant continued Pap testing for cervical cancer. If the woman’s hysterectomy was done before about 1960, she is likely to still have a cervix because of the type of procedure that was done. It is also important to identify if post-hysterectomy women have remaining ovary(ies), as about 5% of ovarian cancers occur in women with previous hysterectomy (McIntosh).