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Pap smear

Definition

A Pap smear is a microscopic examination of cells scraped from the opening of the cervix. The cervix is the lower part of the uterus (womb) that opens at the top of the vagina.

It is a screening test for cervical cancer.

Alternative Names

Papanicolaou test

How the test is performed

You will lie on a table and place your feet in stirrups. The health care provider will insert an instrument (called a speculum) into the vagina and open it slightly to see inside the vaginal canal. Cells are gently scraped from the cervix area, and sent to a lab for examination.

How to prepare for the test

Tell your health care provider if you:

  • Are taking any medications or birth control pills
  • Have had an abnormal Pap smear
  • Might be pregnant

Avoid the following for 24 hours before the test:

  • Douching
  • Having intercourse
  • Taking a bath
  • Using tampons

Avoid scheduling your Pap smear while you have your period (are menstruating), because it may affect the accuracy of the Pap smear. If you are having abnormal bleeding, your doctor may still recommend you have the test done.

Empty your bladder just before the test.

How the test will feel

A Pap smear may cause some discomfort, similar to menstrual cramps. You may also feel some pressure during the exam.

You may bleed a little bit after the test.

Why the test is performed

The Pap smear is a screening test for cervical cancer. Most cervical cancers can be detected early if women has routine Pap smears and pelvic examinations.

Screening should start at age 21. After the first test:

  • Woman should have a Pap smear ever 2 years to check for cervical cancer.
  • If you are over age 30 or your Pap smears have been negative for 3 times in a row, your doctor may tell you that you only need a Pap smear every 3 years.
  • If you or your sexual partner have other new partners, then you should have a Pap smear every 2 years.
  • After age 65-70, most women can stop having Pap smears as long as they have had three negative tests within the past 10 years.
  • If you have a new sexual partner after age 65, you should begin having Pap smear screening again.

You may not need to have a Pap smear if you have had a total hysterectomy (uterus and cervix removed) and do not have a history of cervical dysplasia (abnormal cells), cervical cancer, or other pelvic cancer.

Normal Values

A normal (negative) value means there are no abnormal cells present.

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Abnormal results are grouped as follows:

  • ASCUS or AGUS (atypical cells of uncertain significance): These changes may be due to HPV infection, but may also mean there are precancerous changes.
  • LSIL (low-grade dysplasia) or HSIL (high-grade dysplasia): This means precancerous changes are likely to be present; the risk of cervical cancer is greater with HSIL.
  • Carcinoma in situ (CIS): This usually means the abnormal changes are likely to progress to cancer.
  • Atypical squamous cells (ASC–H): This means abnormal changes have been found and may be HSIL.
  • Atypical glandular cells (AGC): Cell changes are seen that suggest precancer of the upper part of the cervical canal or inside the uterus.

When a Pap smear shows abnormal changes, further testing or follow-up is needed. The next step depends on the results of the Pap smear, your previous history of Pap smears, and risk factors you may have for cervical cancer.

This may include:

  • Colposcopy-directed biopsy
  • An HPV test to check for the presence of the HPV virus types most likely to cause cancer

For minor cell changes, doctors usually recommend having a repeat Pap smear in 3-6 months.

What the risks are

Special considerations

The Pap smear test is not 100% accurate. Cervical cancer may be missed in a small number of cases. Fortunately, cervical cancer develops very slowly in most women and follow-up Pap smears should identify worrisome changes in time for treatment.

Make sure your doctor knows about all the medicines you are taking. Some, including estrogen and progestins, may affect the result of your Pap smear.

Photo

Female reproductive anatomy Pap smear Uterus Pap smear

References

ACOG Practice Bulletin No. 99: management of abnormal cervical cytology and histology. Obstet Gynecol. 2008;112(6):1419-1444.

ACOG Committee on Gynecological Practice. ACOG Practice Bulletin No. 109: Cervical Cytology Screening. Obstet Gynecol. 2009 Dec;114(6):1409-1420.

Cervical cancer in adolescents: screening, evaluation, and manage- ment. Committee Opinion No. 463. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2010;116:469–72.

Noller KL. Intraepithelial neoplasia of the lower genital tract (cervix, vulva): etiology, screening, diagnostic techniques, management. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2007:chap. 28.

Revision

Last reviewed 2/28/2011 by Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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