Preparing for a colonoscopy
A colonoscopy is the gold standard screening to check for signs of colorectal cancer. Doctors recommend getting a colonoscopy on a routine basis. This test increases your chance of finding cancer early when it’s more treatable.
Advocate Health Care offers colonoscopies and other colorectal cancer screenings in multiple locations throughout the Chicago metro area. With easy-to-schedule appointments, Saturday availability and phone consultations, we make it simple to get the care you need. Before your colonoscopy, learn about how to prepare and what to expect.
Colonoscopy preparation
Getting a clear view of your colon and rectum is an important part of your colonoscopy. That’s why it’s essential to empty your colon completely before the test.
Your doctor usually gives you a few choices for colonoscopy prep. Some are prescription and others are available over-the-counter. Colonoscopy preparation typically involves taking a laxative to clear your bowels and electrolytes to prevent dehydration. Some people may need to perform an at-home enema, injecting a liquid and stool softener through the rectum, to stimulate bowel movements.
Your doctor will give you specific written instructions for your colonoscopy prep. In general, they instruct you to:
- Avoid colored liquids and all solid foods for 12 to 24 hours before your test
- Stop eating and drinking altogether by midnight on the day of your appointment
- Take a pill or liquid laxative
Some people need to adjust their medications or stop taking them briefly before the colonoscopy. Your doctor will let you know if you need to make any medication changes.
Plan to stay home throughout your colonoscopy preparation. Follow your doctor’s directions carefully. If your colon isn’t completely empty, you may have to reschedule the colonoscopy for another day.
What happens during a colonoscopy?
When it’s time for your colonoscopy, a staff member takes you to a preop room. You change into a hospital gown, wearing nothing else underneath. A nurse then takes you to the procedure room. You usually receive intravenous (IV) sedation so that you stay asleep and relaxed during the procedure.
During a colonoscopy:
- You lie on an exam table positioned on your side with your knees bent and drawn to your chest.
- Your doctor inserts a thin, flexible tube (colonoscope) into your anus. The colonoscope has a light and camera that lets your doctor view your large intestine (colon) and rectum.
- Your doctor sends air or carbon dioxide through the colonoscope to inflate your colon. They examine your colon and rectum, looking for small growths (polyps) or other irregularities.
- If your doctor finds polyps, they may remove the growths by placing special tools through the colonoscope.
- Your doctor may also take a small tissue sample (biopsy) to check in a laboratory.
Common questions about a colonoscopy
You usually receive deep sedation during a colonoscopy. This means that you’re asleep throughout the procedure. Some people prefer a milder sedation level where you remain awake but don’t remember the procedure. Your doctor will discuss sedation options with you before your test.
A colonoscopy shouldn’t be painful. In fact, you are usually asleep during the procedure and don’t feel anything.
Because your doctor sends air into your colon, you may have some mild discomfort or cramping after a colonoscopy. You may have minor bleeding or pain for a short period if you had a biopsy.
A colonoscopy usually lasts 30-45 minutes. With preop and recovery time, your appointment may take around two hours.
You spend about an hour in a recovery room after a colonoscopy. The initial effects of the sedative start to wear off after an hour, but it can take up to a day for the sedative to fade completely.
Plan to take the rest of the day off work and arrange for someone to drive you home. You can usually resume your typical activities the next day.
Your doctor will tell you the results of your colonoscopy in the recovery room after you wake up. They’ll let you know if they found and removed polyps or if they performed a biopsy. You’ll receive written results within a few days. If you had a biopsy, it might take several days or weeks to get the results from the lab.
If colorectal cancer is found, your doctor may recommend additional diagnostic procedures to determine the cancer's stage, including whether it has spread to other organs.
Advanced diagnostics include:
- Magnetic resonance imaging (MRI): Diagnostic procedure that combines radiofrequencies and a computer to create detailed images of body tissues. An endorectal MRI uses a probe placed into the rectum to provide a more accurate view of cancer within the rectum.
- Positron emission tomography (PET) scan: Nuclear medicine test that is helpful in detecting cancer and determining whether the cancer has spread.
- Computed tomography (CT or CAT scan): Assists with staging a cancer by identifying whether cancer has spread to other organs. CT scan is a diagnostic imaging procedure that combines multiple X-rays and computer technology to produce cross-sectional images ("slices") of organs, bones, muscle and other tissue.
- Tissue biopsy: Small sample of tissue is taken and analyzed to confirm whether it is malignant (cancerous) or benign (noncancerous).
Schedule your colonoscopy
Are you at risk for colon cancer?
Colon cancer is the third most common cancer among men and women in the U.S. Our colorectal health quiz determines your estimated lifetime risk for colon cancer and gives you an idea of what to do next based on your results.