Anoscopy
Reviewed
Also called: Anoscopy, High-resolution anoscopy
An anoscopy is a procedure that uses a lighted scope (anoscope) to examine the lining of the lower rectum and anus. It helps diagnose conditions such as hemorrhoids, anal fissures, polyps, inflammation, and cancer. A related high-resolution anoscopy uses a magnifying device (colposcope) to better detect abnormal cells.
Specimen: Not applicable (procedure). If a biopsy is performed, the specimen is a tissue sample from the anus or lower rectum.
Why this test may be ordered
- To evaluate symptoms such as blood in stool, itching around the anus, swelling, discharge, or painful bowel movements.
- To screen for anal cancer in people with HIV (especially men who have sex with men and adults age 45 or older).
- To investigate possible hemorrhoids, anal fissures, polyps, or inflammation.
Preparation and collection
You may want to empty your bladder and/or have a bowel movement before the test for comfort. Your provider may suggest avoiding anything inserted into the anus (such as medicines, other products, or anal sex) for 24 hours prior. Follow any specific instructions your provider gives you.
You will remove your underwear and lie on your side, stomach, or bend over the exam table. The provider inserts a gloved, lubricated finger into the anus (digital rectal exam), then a lubricated anoscope about two inches into the anus. If abnormal cells are suspected, a swab or other tool may collect a tissue sample (biopsy). For high-resolution anoscopy, a swab with acetic acid is used to make abnormal cells turn white, and a colposcope provides magnification.
Very little risk. You may have discomfort, minor bleeding when the anoscope is removed, especially if you have hemorrhoids. Soreness or minor bleeding can last for a few days. If a biopsy is taken, there is a small risk of bleeding or infection.
Understanding results
An anoscopy provides a direct view of the lower rectum and anus. The procedure can help identify various conditions, but a biopsy is often needed to confirm a diagnosis. Your healthcare provider will interpret the findings together with your symptoms and medical history. The results below are not a confirmed diagnosis; they indicate a likelihood based on visual inspection.
- No visible abnormalities: Lower likelihood of significant anorectal conditions such as hemorrhoids, fissures, polyps, infection, or cancer. Limitation: A normal anoscopy does not rule out all conditions; further testing may be needed if symptoms persist or if early changes were not visible. Next step: If your symptoms continue, your provider may recommend additional evaluation or a high-resolution anoscopy.
- Abnormal findings (e.g., hemorrhoids, fissures, polyps, suspicious cells): Higher likelihood of anorectal conditions such as hemorrhoids, fissures, polyps, infection, or cancer, but these findings are not diagnostic by themselves. Limitation: Anoscopy findings alone are not diagnostic for cancer; a biopsy is necessary for confirmation. False-positive and false-negative results are possible. Next step: Your provider may order a biopsy of any visible abnormal tissue. Treatment options will be discussed based on the biopsy results.
- Discomfort or minor bleeding may occur during or after the procedure.
- Standard anoscopy may miss small tissue changes that high-resolution anoscopy could detect, which may lead to false-negative results.
- Findings from anoscopy alone are not diagnostic for cancer; biopsy is required for confirmation.
What to do next
Your healthcare provider will discuss the findings and may recommend a biopsy, further imaging, or treatment options. Follow your provider's recommendations for follow-up care.
- Have you had any symptoms such as blood in stool, itching, pain during bowel movements, or discharge from the anus?
- Do you have any risk factors for anal cancer, such as HIV, or other conditions that weaken the immune system?
- Have you had any previous anorectal procedures or treatments?