What is a colonoscopy?

A colonoscopy is a procedure that lets your doctor see the inside of your entire colon—or large intestine. It uses a flexible tube with a light and a camera to look for signs of various colon conditions, and it’s also a commonly performed screening test for colorectal cancer.  

In some cases, your doctor may use a colonoscopy to take tissue samples or remove abnormal tissue. For example, polyps can be removed during colonoscopy to prevent them from progressing to colon cancer.

Watch Dr. Amaning address some common colonoscopy questions

colonoscopy patient sitting in a park with his dog

Why might I need a colonoscopy?

You might need a colonoscopy for polyp and colon cancer screening, or to diagnose and determine treatment for a digestive condition. Early detection is key to preventing and reducing the risk of colon cancer and a colonoscopy can detect colon cancer even if you have no symptoms.

If you are having digestive symptoms, a colonoscopy may allow your doctor to diagnose the source of your symptoms, so you can choose the appropriate course of treatment.

At what age should you get a colonoscopy?

You should talk to your doctor about colorectal cancer screenings, including colonoscopy, beginning at age 45. In 2021, the age to start colorectal cancer screenings was lowered from age 50 to 45, as colon cancer rates are rising in younger people.

Early screening for higher risk 

Talk to your care team if you have a family history of colorectal cancer, have inflammatory bowel disease, have a hereditary colorectal cancer syndrome or have any other risk factors. If your risk is high, the age at which you start screening may be earlier than those with an average risk. 

How often should you get a colonoscopy?

If your colonoscopy screening is normal, then you typically only need to repeat the screening every 10 years. Based on other findings like polyps, inflammatory bowel disease and family history, some people need to repeat a colonoscopy more frequently.

Once you reach age 75, you should talk with your doctor to decide if continuing screening is right for you based on your health needs.

doctor in scrubs performing a colonoscopy on a patient

How to prepare for a colonoscopy

To get ready for your colonoscopy, you’ll need to do a prep ahead of time to clean out your large intestine. This is important to give your doctor a clear view of the inside of your entire colon, so be sure to follow your doctor’s specific instructions.

It’s helpful to review your prep instructions several days before your procedure so that you can shop for supplies ahead of time. You’ll also want to talk to your doctor about any medications or supplements you take, as you may need to stop taking some of these before your procedure.  Make sure you plan to have a support person with you on the day of your colonoscopy to drive you home after your procedure.

The colonoscopy procedure

A colonoscopy is a routine outpatient endoscopy test, meaning it doesn’t require you to stay in the hospital overnight. Your care team will give you anesthesia to put you to sleep or use sedative medications. While the procedure is quick, it requires preparation, including dietary changes, a few days before in addition to drinking the laxative solution.

Many people are hesitant to have a colonoscopy because of the prep, but your care team can provide helpful tips and instructions for your procedure. Today, there are various medication options available to help you prepare for your colonoscopy. Talk with your doctor about the right prep for your needs.

Before the procedure

Your doctor will give you step-by-step instructions on diet changes and adjustments to medications (if needed) in the days before your procedure. A few days before your colonoscopy, it is recommended to begin eating a diet low in fiber.  The day before your procedure, you’ll need to switch to a clear liquid diet—meaning you can only have liquids like water, broth, black tea or coffee, sports drinks, soda, or juice—avoiding anything with red, blue or purple dyes.

Depending on the time of your colonoscopy, you’ll take laxative medications—either in liquid or pill form—the evening before or in the evening and the morning of your procedure. These medications will make you go to the bathroom often to clean your colon. Plan to stay near a bathroom, make yourself comfortable and keep any needed supplies with you until your prep is complete.

Understanding the results

Your doctor will talk to you about the initial results of your colonoscopy right after you wake up from your procedure. If tissue samples were sent to the lab for more testing, those results typically take a few days. Based on the visual exam of your colon and any pathology results, you’ll be given either a normal or abnormal result for your procedure.

Normal results

A normal result means nothing abnormal was found. Your colon looked normal and healthy and showed no signs of cancer or a digestive condition. Most people will follow up with another colonoscopy screening in 10 years, but you may need one sooner if you have other risk factors like a family history of colon cancer.



Abnormal results

An abnormal result means your care team found an abnormality in the colon. This could include changes in the tissues due to a variety of digestive conditions, including inflammation, diverticulosis, narrowing, scarring or bleeding. You could also receive an abnormal result if your doctor finds precancerous or cancerous polyps. Depending on what is found, your doctor will work with you to confirm your diagnosis and plan your next steps.

Frequently asked questions