A Pap smear is a test that is used to detect abnormal cells on the cervix. An abnormal Pap smear result is often is the first indicator of the presence infection, inflammation or cervical cancer. If the Pap smear indicates the presence of abnormalities, follow-up testing will be necessary to diagnose the precancer or cancerous condition.

Since the Pap smear was developed by Dr. George Papanicolaou more than 60 years ago, the rate of death from cervical cancer has dropped dramatically. Women who have regular Pap smears are unlikely to develop an invasive form of this disease. The Pap smear is effective for diagnosing precancerous changes or cervical cancer in its early stages. When cervical cancer is detected early, it is highly treatable with an improved success rate.

Each year, 55 million Pap tests are performed in the United States, according to the National Cancer Institute. Approximately 6 percent of these show abnormal results that require medical follow-up.

The American Cancer Society (ACS) recommends that women have their first Pap smear three years after first having sexual relations, or at age 21 whichever occurs first. Other experts suggest these tests should begin no later than age 18.

After the age of 21 years, the ACS recommends the following schedule:

Women with certain risk factors may need to be screened annually or on a more frequent schedule if recommended by their physician. These women may have the following lifestyle risk factors:

• History of sexual activity as a teen, especially if there is a history of more than one sexual partner.
  
  
• Multiple sex partners at present.
  
  
• Partner who began sexual activity at an early age or who had many previous sexual partners.
  
  
• Infection with the human papillomavirus (HPV), the virus that can cause genital warts. Although the types of HPV that cause genital warts (e.g., HPV types 6 and 11) are considered low risk for precancerous cervical changes, infection with certain high-risk forms of the virus (e.g., HPV types 16 and 18) are a major cause of cervical cancer and are also associated with other genital cancers including vulvular and anal.
  
  
• History of other sexually transmitted diseases (e.g., herpes, chlamydia).
  
  
• Tobacco use.

Other factors that may warrant an annual or more frequent Pap smear include:

• Family history of cervical cancer.
  
  
• Diagnosis of cervical cancer or previous precancerous Pap smear.
  
  
• Exposure to DES (diethylstilbestrol) before birth. DES is a potent synthetic estrogen that was used from 1940 to 1970.
  
  
• Weakened immune system due to chronic illness (e.g., HIV/AIDS), organ transplant, chemotherapy treatment or prolonged corticosteroid use.

A Pap smear is typically conducted as part of a woman’s pelvic examination during a regular gynecological visit. Pelvic exams include examination of the uterus, vagina, ovaries, fallopian tubes, bladder and rectum.

Women who have had a total hysterectomy (surgical removal of the uterus and cervix) should ask a physician whether they need to continue to have Pap smears. In many cases, women who have had hysterectomies performed for noncancerous reasons – such as uterine fibroids – may be allowed to skip Pap smears as long as they continue to have regular pelvic examinations. However, in cases where the results indicate cervical malignancies, a Pap test will be used to screen for vaginal or vulva abnormalities that could indicate a recurrence. In these situations, a yearly Pap test will likely be recommended.