Pap test

A Pap test removes a small sample of cells from the surface of the cervix. Samples of cells from the vagina may also be taken. It is done to look for changes to the cells in the cervix or vagina.

A Pap test may also be called a Pap smear.

A Pap test is mainly used to:

• screen for and help diagnose precancerous conditions of the cervix and cervical cancer
• help diagnose precancerous conditions of the vagina and vaginal cancer
• diagnose infection and inflammation in the vagina
• check for abnormal cell changes or see if abnormal cells return to normal
• monitor precancerous conditions or see if cancer comes back (recurs) after treatment

It is better to have a Pap test when you aren’t having your period. Avoid having a Pap test if you’re being treated for a cervical or vaginal infection — wait at least 2 weeks after treatment has ended.

Some products may wash away or hide abnormal cells. Avoid using the following 48 hours before your test:

• vaginal douches (inserting a solution into the vagina and flushing it out)
• vaginal medications
• contraceptive (spermicidal) creams, foams or jellies

Avoid having sex.

A Pap test may be done as part of a regular checkup or during a pelvic exam. It is usually done in a doctor’s or nurse’s office. It only takes a few minutes. You will need to urinate (pee) to empty your bladder before the test.

A Pap test is done laying on your back with your feet supported by footrests. The doctor or nurse will place a speculum into the vagina. The speculum keeps the vagina open so they can see the upper part of the vagina and cervix. Using a cotton swab, brush, or small spatula, the doctor or nurse gently scrapes the surface of the cervix to pick up cells. Samples of cells from the vagina can also be taken during a Pap test. You may feel some discomfort or pressure during the test, but it is not usually painful. You may have some light bleeding from the vagina afterwards.

The collected cells are smeared onto a glass slide or placed in a special liquid. The sample is sent to a lab to be examined under a microscope. The liquid containing the sample of cells may also be used to test for human papillomavirus (HPV).

A Pap test result may be described as normal or abnormal. Normal results are also sometimes described as negative.

A normal result means that no abnormal or cancerous cells were found.

If your Pap test results are abnormal, it doesn’t always mean that you have a precancerous condition or cancer. Some abnormal cells return to normal on their own. Other abnormal cells or precancerous changes in the cervix or vagina may develop into cancer over time if they aren’t treated.

Abnormal cells in the cervix or vagina are classified based on the type of cell that has changed and how different they look from normal cells.

Squamous cells are on the surface of the cervix or vagina. The most common abnormal Pap result is atypical squamous cells of undetermined significance (ASC-US). This means some squamous cells don’t look completely normal, but it’s not clear if the abnormal cells are caused by an HPV infection.

Changes to squamous cells can also be described as squamous intraepithelial lesions (SILs). SILscan be low grade (mild changes) or high grade (moderate or severe changes).

• Low-grade SIL (LSIL) means the cells have mild changes in size and shape, usually caused by an HPV infection.
• High-grade SIL (HSIL) means there are moderately or severely abnormal cells that could become cancer if not treated.

Other changes to squamous cells include the following:

• Atypical squamous cells (ASC-H) means some cells don’t look completely normal. They may be high-grade SIL (HSILs), but it’s not clear.
• Squamous cell carcinoma (SCC) means there are cancer cells in the lining of the outer surface of the cervix.

Glandular cells are on the inside of the cervical canal. Changes to these cells are described as one of the following:

• Atypical glandular cells (AGC) means some cells don’t look normal.
• Adenocarcinoma in situ (AIS) means there are cancer cells in the glandular tissue lining the inside of the cervix, but there has been no spread into the deeper tissues of the cervix or surrounding tissue.
• Adenocarcinoma means there is cancer in the lining inside the cervix (endocervical cancer).

Changes to cervical cells are most commonly caused by infection with HPV. Sometimes cells infected with HPV become precancerous.

Changes to the cervical or vaginal cells may also be caused by:

• a viral, bacterial or yeast infection
• inflammation
• non-cancerous growths such as polyps or cysts

Your doctor will recommend more tests, procedures, follow-up care or treatment.

Follow-up for an abnormal Pap test depends on how severe the results are. Treatment may not be needed because some abnormal cells change back to normal on their own. Other abnormal cells or precancerous changes to cells can develop into cancer if they aren’t treated.

Follow-up tests and procedures for abnormal Pap test results include:

• another Pap test
• an HPV test
• a colposcopy (a procedure that uses a lighted magnifying instrument, called a colposcope, to examine the vulva, vagina and cervix)
• endocervical curettage (a type of biopsy to remove cells from the endocervical canal, which is the passageway from the uterus to the vagina)
• a loop electrosurgical excision procedure (LEEP) or other type of cone biopsy

Find out more about an HPV test and a LEEP.

If you have an abnormal Pap test result when you are pregnant, your doctor will talk to you about next steps. You may have a colposcopy. This procedure typically includes a biopsy, but there is a small chance that removing the abnormal cells will cause bleeding. So doctors usually don’t take a biopsy sample until after you’ve given birth.

A Pap test is the best test we have to find cervical cancer early, but it is not perfect. Screening tests, including the Pap test, have a risk of giving incorrect 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 looks like a precancerous condition, but it actually isn’t. A false-positive result may lead to unnecessary follow-up tests, procedures and anxiety.