A Pap test (also called a Pap smear) is a simple screening test used to look for abnormal cells in the lining of the cervix or anal canal. These areas are lined by squamous cells, which can develop changes over time that may lead to cancer if not detected and treated early. The main purpose of the Pap test is to find precancerous changes (called dysplasia), but it can also detect infections, inflammation, or, in some cases, signs of cancer. The Pap test is named after Dr. George Papanicolaou, who developed the technique.
Pap tests are most commonly performed on the cervix but may also be done on the anal canal in certain people, especially those at higher risk for anal cancer. In both locations, the test works by collecting cells from the surface of the tissue and examining them under a microscope.
The Pap test is used to detect early cell changes that could develop into cervical or anal cancer. These changes are often caused by infection with the human papillomavirus (HPV), a common virus that spreads through skin-to-skin or sexual contact. The test can also identify signs of infection, inflammation, or hormonal changes in the tissue.
A Pap test is a quick procedure done in a doctor’s office or clinic.
For a cervical Pap test:
You will lie on an exam table.
A speculum is gently inserted into the vagina to allow the doctor to see the cervix.
A small brush or spatula is used to collect cells from the surface of the cervix.
For an anal Pap test:
A lubricated swab or brush is gently inserted into the anal canal.
Cells are collected by rotating the brush and then sent to a laboratory for analysis.
The entire process takes only a few minutes and may cause brief discomfort but is generally not painful.
For cervical screening, guidelines recommend:
Ages 21 to 29: Pap test every 3 years.
Ages 30 to 65: Pap test every 3 years, or every 5 years if combined with HPV testing.
After age 65: Screening may be stopped if previous results were consistently normal.
After hysterectomy: You may no longer need Pap tests if the cervix was removed and you have no history of cervical cancer or precancer.
Anal Pap testing may be recommended for individuals at higher risk of anal cancer, including:
People living with HIV.
Men who have sex with men.
Individuals with a history of cervical, vulvar, or vaginal cancer.
Those who engage in receptive anal sex.
People who are immunocompromised.
Your doctor can help you decide whether you need cervical, anal, or both types of Pap testing.
Pap test results are based on the types of cells seen under the microscope and whether any abnormalities are present. Each result provides important information about your risk of developing cervical or anal cancer and helps guide the next steps in your care.
Common results include:
Negative for intraepithelial lesion or malignancy (NILM): This means that no abnormal or cancerous cells were found. Your result is considered normal, and you can continue routine screening as recommended.
ASC-US (Atypical Squamous Cells of Undetermined Significance): Some squamous cells appear slightly abnormal, but it is unclear what caused the changes. These results are often caused by a temporary HPV infection or inflammation. Your doctor may recommend HPV testing or a follow-up Pap test in a few months.
LSIL (Low-Grade Squamous Intraepithelial Lesion): This means there are mild changes in the squamous cells, usually caused by an HPV infection. In many cases, these changes go away on their own, but your doctor may suggest closer monitoring or additional testing.
HSIL (High-Grade Squamous Intraepithelial Lesion): This result shows more serious abnormalities in the squamous cells. Without treatment, these changes have a higher chance of developing into cancer. Your doctor will likely recommend further testing, such as a colposcopy and biopsy.
AGC (Atypical Glandular Cells): Abnormalities were seen in the glandular cells, which are different from squamous cells and found higher up in the cervix or inside the uterus. These changes may be linked to precancer or cancer and usually require additional testing to find the cause.
Squamous cell carcinoma: Cancerous cells were found that developed from squamous cells. This means that invasive squamous cell carcinoma may be present, and immediate follow-up is needed.
Adenocarcinoma: Cancerous cells were found that developed from glandular cells, such as those lining the cervical canal or uterus. This diagnosis also requires prompt follow-up and further testing.
Your doctor will explain your Pap test results and recommend the appropriate next steps based on your individual situation.
What did my Pap test show?
Do I need follow-up testing or treatment?
Should I be tested for HPV?
Based on my age and medical history, how often should I have a Pap test?