What Is an Anal Pap Smear?

What to expect when undergoing this test

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In This Article

An anal Pap smear is a screening test for anal cancer in men and women. Also called anal cytology, it's performed by taking a sample of cells from the anus that are then examined under a microscope in a lab. It's not a diagnostic test, but rather looks for precancerous or cancerous cells. If abnormal cells are found, further testing will be necessary. The anal Pap does not test for colon or rectal cancer.

The anal Pap smear is regarded as the counterpart of the cervical Pap smear, which is named after George Papanicolaou, the Greek doctor who invented the test in the 1940s.

Purpose of Test

The anal Pap test screens for changes in squamous cells that line the anus as well as the cervix. Changes in these cells may suggest that cancer is likely to develop or that cancer has already developed.

As with cervical cancer, human papillomavirus (HPV) is responsible for most cases of anal cancer. In fact, according to the National Cancer Institute (NCI), more than 90% of anal cancers are caused by HPV, which is also responsible for penile cancer as well as head and neck cancer.

Of the hundreds of strains of HPV, the two most often associated with anal cancer are HPV 16 and HPV 18. Both are targets of the HPV vaccine.

Screening Guidelines

No national organization has issued routine anal cancer screening guidelines for the general population. However, because people living with HIV are most at risk of HPV infection, the HIV Medicine Association of the Infectious Diseases Society of America (HIVMA) does recommend that certain people living with HIV have anal Pap tests:

The American Cancer Institute (ACS) includes additional groups that are at increased risk of anal cancer:

  • Women who have had vaginal, vulvar, or cervical cancer
  • Anyone who has had an organ transplant
  • Anyone with a history of genital warts

In addition, anal cancer is more common among people who are over 50, as well as people who smoke.

The ANCHOR Study

In order to pin down screening guidelines for people who have HIV, the NCI is conducting a nationwide study of those with high-grade squamous intraepithelial lesions (HSILs), the type that can develop into cancer. Enrolled subjects will be treated or monitored every six months for a minimum of five years. ANCHOR stands for Anal Cancer HSIL Outcomes Research.

Before the Test

There is nothing you will need to do in advance of your test to prepare for it. However, there are a number of things you should not do beforehand to ensure accurate results. During the 24 hours before having an anal Pap smear, do not:

  • Have receptive anal intercourse
  • Put any creams, lubricants, or medications into your anus
  • Insert sex toys or other objects into your anus
  • Douche or use enemas

If for any reason you do not adhere to any of these guidelines, call your provider to ask if you should reschedule your test.

Timing

The actual Pap smear will take about five minutes, but you'll need to block off more time than that. Schedule your day to account for travel to and from the testing site, possible paperwork when you arrive (particularly if you are seeing the provider who will perform the screening for the first time), and waiting.

Timing Tip

When you call to make your appointment, ask if there are certain days or times of day during which there is likely to be no wait or at least a very short wait.

Location

An anal Pap smear takes place in an exam room of a doctor's office, hospital, or clinic. The room will contain equipment you're familiar with (a blood pressure cuff, for example, and tongue depressors and other items). If you're a woman and a gynecologist will be performing your anal Pap test, the exam table will be outfitted with stirrups.

What to Wear

You will need to remove your clothing from the waist down and put on a medical gown for the test, so you may want to think about that when you dress. Women might choose to wear a dress or a skirt so all they need to take off are shoes and underwear, for instance. Medical exam rooms tend to be chilly so you may want to wear or bring a pair of socks.

Cost and Health Insurance

Health insurance often doesn't cover anal Pap testing. If you have insurance, check the details of your plan or ask a representative if your screening will be covered. If not, you will need to pay out of pocket for the procedure.

You'll also have to pay for anal cancer screening yourself if you have Medicaid nor Medicare, as neither covers the test. Ask your doctor's office for an estimate of how much it will cost.

What To Bring

Bring your insurance card and co-pay (if you have one) with you to the appointment. If you're having any anal or rectal symptoms, such as pain or discharge, write down the details to share with the doctor. Jot down any questions you may have about the procedure or anal cancer in general as well.

If the provider is one you've never seen before, you may be asked to bring your medical records.

During the Test

The anal Pap smear is quick and simple. Using a moistened swab (similar to a cotton swab but with a synthetic tip because cotton fibers can interfere with the sample), a clinician collects cell samples from the anal canal by swabbing all surfaces of the anus and rectum.

Pre-Test

When you arrive for your test, you will check in with a receptionist. If it's your first visit to the doctor's office or clinic, you may have to fill out new new-patient forms, including a medical history. You may need to stay in the waiting room for a while.

When it's time for your test, a member of the office staff will escort you to the room where it will be performed. You'll be given a medical gown and instructed to undress from the waist down before putting it on. They'll then leave the room to give you privacy while you change. Feel free to leave your socks on if you think you will get cold.

After allowing ample time for you to get ready, the clinician who will perform the exam will knock on the door before coming in. A nurse, medical student, or other authorized person may accompany them to act as a chaperone, per recommendations by the American Medical Association.

The doctor will ask you to get into position for the test. The most common position is lying on the left side with the knees drawn up toward the chest, but other positions are acceptable, depending on the practitioner's preference.

Throughout the Test

To perform the test, the doctor will move the hospital gown out of the way. They will gently widen the area around your anus with one hand and with the other insert a moistened swab with a synthetic tip approximately two to three inches into your anus.

They will rotate the swab 360 degrees, pressing it slightly against your skin in order to pick up a cell sample. Continuing to rotate the swab, they will slowly withdraw it. This may cause mild discomfort, but it should take no more than 30 seconds for the clinician to collect enough cells, after which they will cover you with the gown and instruct you to sit up slowly.

Working quickly, the doctor will prepare the cell sample for the pathology lab by either spreading it onto a slide or placing it in a vial filled with a preservative and shaking it vigorously. This method, called liquid-based cytology, washes away blood and other substances that might obscure abnormalities and skew the results.

Cell samples from the anus must be prepared within 15 seconds of being collected or they may dry out, according to the University of California, San Francisco.

Post-Test

Unless you're instructed otherwise, you'll likely be left alone to put your clothes back on. You may be asked to stop by the receptionist's desk on the way out or told you're free to leave once you're dressed. If you haven't been told when to expect the results of your test, you may want to ask.

Interpreting Results

Your anal cell samples will be sent to a lab, where technicians will examine them under a microscope in order to identify cellular changes that may indicate cancer. It will take about two weeks to get results.

  • Negative: All cells were found to be normal.
  • Unsatisfactory: The sample taken wasn't able to be tested (it was too small, say, or somehow became contaminated) and the test will need to be repeated.
  • ASCUS (Atypical Squamous Cells of Undetermined Significance): Some atypical (or unusual) cells are present. These may indicate infection or inflammation.
  • ASC-H (Atypical Squamous Cells, cannot exclude a High-Grade Anal Squamous Intraepithelial Lesion (HSIL): This result could indicate mild abnormalities or something more severe.
  • LSIL (Low-Grade Anal Squamous Intraepithelial Lesion): Some abnormal cells are present.
  • HSIL (High-Grade Anal Squamous Intraepithelial Lesion): Severe abnormality of cells that could be precancerous. More testing will be needed.
  • Squamous Carcinoma: Cell changes that may indicate cancer. If you get this result, your provider will order a biopsy.

Follow-Up

Generally, the physician will have the results in just a few days and they or someone from their office will call to share them with you. Sometimes test results are sent in the mail, but this is likely to only happen if they're normal or the doctor is not concerned about the findings. If you receive your test results by mail and don't understand them, don't hesitate to call the provider to ask any questions you have.

If abnormal cells are found, depending on the grade you may need to be monitored or you will be asked to come in for further testing, which can include a digital anal exam (exam of your anus using gloved hands), a biopsy, or an anoscopy.

An anoscopy is a test in which a small light instrument called an anoscope is inserted into the anus in order to illuminate the skin lining the anus and rectum. Often, a high-resolution anoscopy (HRA) will be recommended for a follow-up to an abnormal anal Pap. This type of anoscopy is done with a high-resolution instrument and can be more precise than a regular anoscopy.

Sometimes an anoscopy is done in conjunction with a biopsy.

A Word From Verywell

It's normal to feel anxious before, during, and after this procedure, especially because it is in a sensitive and private area of your body. But chances are, your anal Pap test will be a quick and relatively easy experience.

Stay calm and remember that this is just a screening tool, not a diagnostic test. Even if you receive positive results on your anal Pap smear, that doesn't mean that you have or will develop cancer. Often, abnormal lesions resolve on their own and do not become cancerous.

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Article Sources
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