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.
How the Test is Performed
You will lie on a table and place your feet in stirrups. The doctor or nurse will place an instrument (called a speculum) into the vagina and open it slightly. This allows the doctor or nurse to better see inside the vagina and cervix.
Cells are gently scraped from the cervix area, and sent to a lab for examination.
How to Prepare for the Test
Make sure your doctor or nurse knows about all the medicines you are taking. Some birth control pills that contain estrogen or progestin may interfere with test results.
Also tell your doctor or nurse if you:
- Have had an abnormal Pap smear
- Might be pregnant
Avoid the following for 24 hours before the test:
- 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.
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 a woman has routine Pap smears.
Screening should start at age 21. After the first test:
- You 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 have not had an abnormal Pap smear, cervical cancer, or other pelvic cancer.
A normal (negative) value means there are no abnormal cells present.
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
- This result means there are atypical cells of uncertain significance
- The changes may be due to the human papillomavirus (HPV, the virus that causes genital warts
- They may also mean there are changes that may lead to cancer
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 result usually means the abnormal changes are likely to lead to cervical cancer
Atypical squamous cells (ASC–H):
- Abnormal changes have been found and may be HSIL
Atypical glandular cells (AGC):
- Cell changes that may lead to cancer are seen in 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.
Follow-up testing 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.
The Pap smear test is not 100% accurate. Cervical cancer may be missed in a small number of cases. Most of the time, cervical cancer develops very slowly and follow-up Pap smears should identify worrisome changes in time for treatment.
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.
Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. 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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