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What Is a Pap Test?
A Pap test is a test of a sample of cells taken from a woman’s cervix or vagina. The test is used to look for changes in the cells of the cervix or vagina that show cancer or conditions that may develop into cancer.
It is the best tool to detect precancerous conditions and hidden, small tumors that may lead to cervical cancer. If detected early, cervical cancer can be cured.
Make sure you get a Pap test to check for cervical cancer every 3 years if you are 21 or older. If you are age 30-65, you can get both a Pap test and HPV test every 5 years. Older than that, you may be able to stop testing if your doctor says you’re low risk. If you are sexually active and have a higher risk for STDs, get tests for chlamydia, gonorrhea, and syphilis yearly. Take an HIV test at least once, more frequently if you’re at risk.
Why it’s done
A Pap smear is used to screen for cervical cancer. The Pap smear is usually done in conjunction with a pelvic exam. In women older than age 30, the Pap test may be combined with a test for human papillomavirus (HPV) — a common sexually transmitted infection that can cause cervical cancer in some women.
Who should have a Pap smear?
You and your doctor can decide when it’s time for you to begin Pap testing and how often you should have the test.
In general, doctors recommend beginning Pap testing at age 21.
How often should Pap smear be repeated?
Doctors generally recommend repeating Pap testing every 3 years for women ages 21-65.
Women age 30 and older can consider Pap testing every 5 years if the procedure is combined with testing for HPV.
If you have certain risk factors, your doctor may recommend more-frequent Pap smears, regardless of your age. These risk factors include:
- A diagnosis of cervical cancer or a Pap smear that showed precancerous cells
- Exposure to diethylstilbestrol (DES) before birth
- HIV infection
- Weakened immune system due to organ transplant, chemotherapy or chronic corticosteroid use
You and your doctor can discuss the benefits and risks of Pap smears and decide what’s best for you based on your risk factors.
I had a hysterectomy. Do I still need Pap tests?
It depends on the type of hysterectomy (surgery to remove the uterus) you had and your health history. Women who have had a hysterectomy should talk with their doctor about whether they need routine Pap tests.
- If you no longer have a cervix because you had a hysterectomy for reasons other than cancer, you do not need Pap tests.
- If you had a hysterectomy because of abnormal cervical cells or cervical cancer, you should have a yearly Pap test until you have three normal tests.
- If you had your uterus removed but you still have a cervix (this type of hysterectomy is not common), you need regular Pap tests until you are 65 and have had three normal Pap tests in a row with no abnormal results in the last 10 years.
A normal result means there are no abnormal cells present. The Pap 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 tests should find any changes in time for treatment.
What Abnormal Results Mean
Abnormal results are grouped as follows:
ASCUS or AGUS
- This result means there are atypical cells, but it is uncertain or unclear what these changes mean
- The changes may be due to HPV
- They may also mean there are changes that may lead to cancer
LSIL (low-grade dysplasia) or HSIL (high-grade dysplasia):
- This means changes that may lead to cancer are present
- The risk of cervical cancer is greater with HSIL
Carcinoma in situ (CIS):
- This result most often means the abnormal changes are likely to lead to cervical cancer if not treated
Atypical squamous cells (ASC):
- 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 test shows abnormal changes, further testing or follow-up is needed. The next step depends on the results of the Pap test, your previous history of Pap tests, and risk factors you may have for cervical cancer.
For minor cell changes, doctors will recommend another Pap test in 6 to 12 months.
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
Risks with a Pap test
Screening tests, including the Pap test, have a risk of giving misleading results.
A false-negative result means that the test doesn’t find cancer or abnormal cells even though they are present. This may occur if the sample doesn’t have enough tissue or cells. It can also happen when abnormal cells in the sample are missed.
A false-positive result means that the test shows abnormal cells even though they are not present. This means that something looked like a precancerous condition, but it actually isn’t. A false-positive result may lead to unnecessary follow-up tests, procedures and anxiety.