Anal Papanicolau ("Pap") smears

Anal Pap smears are currently being evaluated for a possible role as screening tests for anal cancer and pre-cancer. The procedure involves the sampling of cells from the anal canal and uses the same technique as successfully performed in cervical cancer screening.

How is it collected?

Swab and transport medium for anal Pap specimen

It is important that you do not douche (wash inside the anus) before having an anal Pap smear taken.

You will first be asked to take down your lower garments, before lying on your left side. The sample will then be collected by inserting a moistened swab 5cm into the anal canal and firmly rotating it for 1 minute. The material from this swab is then sent to the laboratory for analysis.

Please find attached to the embedded link, a resource that clinicians may find useful in relation to self collection of an anal swab. This chart was developed in conjunction with STIGMA.

Are there any side effects?

The procedure may be a little uncomfortable. There may be some minor bleeding immediately afterwards, particularly for those with pre-existing lesions of the anal canal, such as anal warts. It is possible that you will notice a small amount of blood in your first bowel motion following the procedure, but this should not persist.

What do the results mean?

Results typically take two weeks to become available.

The sensitivity of this test is quite low – in other words, it sometimes misses cases of AIN. Also, on occasions, the result may be misleading. For these reasons, it is only currently performed in specialist centres in Australia, and you must discuss the meaning of your result carefully with your specialist.

The table below lists the common results of anal Pap smears, and gives some possible implications.

Result Other name    Possible implications
Unsatisfactory   Often found in a specimen from a person who has douched the anus before the sample was taken. Needs to be repeated.
Normal   No abnormal cells seen.
Low grade squamous intraepithelial lesion (LSIL) AIN 1  Probable infection with low-risk HPV. Regarded as being at low risk of developing anal cancer.
Atypical squamous cells of uncertain significance ASCUS No seriously abnormal cells seen, but some suspicious cells means that further assessment may be indicated. High Resolution Anoscopy may be appropriate. Sometimes the laboratory divides this category into "ASCUS-L" and "ASCUS"> This is done if there is a suggestion of a low grade ("L") or high grade ("H") abnormality.
High grade squamous intraepithelial lesion AIN 2,
AIN 3
Probable infection with high-risk HPV. Regarded as being at increased risk of developing anal cancer. High resolution anoscopy may be indicated.

Note: None of the above results indicate that cancer is present.