Colonoscopy: What to Expect, Prep, and Recovery

A colonoscopy is an exam of the large intestine (colon and rectum) using a thin, flexible tube with a camera, called a colonoscope. It is the best test to find and prevent colon cancer, because polyps can be found and removed during the same exam. We perform colonoscopies at Valley Digestive Health Center in Arcadia and at USC Arcadia Hospital.

Why a colonoscopy is done

• Colon cancer screening starting at age 45 (earlier if you are at higher risk). See colon cancer screening and polyps.
• Follow-up of a positive stool test (FIT or Cologuard), blood test, or CT scan
• Surveillance after polyps or colon cancer, or with inflammatory bowel disease
• Symptoms: rectal bleeding, iron-deficiency anemia, chronic diarrhea, a change in bowel habits, or unexplained belly pain or weight loss

Polyps are small growths on the lining of the colon. Some can turn into cancer over years, so removing them prevents cancer.

Direct access screening colonoscopy

If you are 45 or older, have no symptoms, and are healthy enough, you may be able to schedule a screening colonoscopy without a separate office visit. Learn about our direct access colonoscopy program.

Colonoscopy with PPO, commercial insurance, or Medicare

• No referral needed on most PPO plans. You can book directly with our gastroenterologists. We are in network with Aetna, Anthem Blue Cross, Blue Shield of California, Cigna, UnitedHealthcare, and Medicare (see accepted insurance).
• Screening colonoscopy for average-risk adults 45 and older is covered at no cost by most PPO and commercial plans under the Affordable Care Act, including removal of polyps found during the exam.
• Diagnostic or surveillance colonoscopy: a colonoscopy for symptoms, or one done less than 10 years after your last because of past polyps, may be subject to your deductible and copay.
• Outpatient center: colonoscopies at Valley Digestive Health Center in Arcadia often cost less than the same procedure in a hospital.
• We obtain any prior authorization your plan requires. See procedure billing for the bills to expect and the codes to give your insurance.

How to prepare

• Medicines: tell us about all your medicines and allergies. Blood thinners, diabetes medicines, and weight-loss injections such as semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) may need to be adjusted. Do not stop a blood thinner without talking to the doctor who prescribed it.
• Health history: tell us about heart or lung problems, diabetes, kidney disease, sleep apnea, or past bowel surgery.
• Diet: eat a low-fiber diet for a few days, then switch to clear liquids the day before.
• Bowel prep: drink the prep as directed, usually split into two doses (the evening before and the morning of the procedure). A clean colon is the most important part of a good exam. Follow our bowel prep instructions exactly.
• A ride home: you will receive sedation, so you must have an adult drive you home. You cannot take a taxi or rideshare alone.

What to expect during the procedure

• An IV is placed, and you receive sedation so you are comfortable and sleepy.
• You lie on your side. The doctor gently passes the colonoscope through the rectum and around the colon, inflating it with carbon dioxide or air for a clear view.
• Polyps are removed and small tissue samples (biopsies) are taken if needed. This is painless.
• The exam usually takes 20 to 40 minutes.

After the procedure

• You will rest in recovery until the sedation wears off. The doctor or nurse will review the findings with you.
• You may feel bloated or crampy and pass gas for a few hours.
• Most people can eat normally afterward unless told otherwise.
• Do not drive, work, drink alcohol, or make important decisions for the rest of the day. Plan to resume normal activities the next day.
• If a blood thinner was stopped, we will tell you when to restart it.
• If polyps or biopsies were taken, we will contact you with the results, usually within 1 to 2 weeks, and tell you when your next colonoscopy is due.

Risks

Colonoscopy is very safe. Serious complications are rare and include bleeding (more likely after removing large polyps, and sometimes days later), a tear (perforation) in the colon wall, and reactions to sedation. Most can be treated without surgery. Like any test, colonoscopy can occasionally miss a polyp, which is why a good bowel prep matters.

Call us or go to the emergency room for severe belly pain, fever, heavy rectal bleeding, or dizziness after the procedure.

How often you need one

• Normal exam, average risk: every 10 years
• Polyps found: every 3 to 10 years, depending on the number, size, and type
• Family history of colon cancer or advanced polyps in a parent, sibling, or child: often every 5 years
• Inflammatory bowel disease: every 1 to 3 years

Make an appointment

Our gastroenterologists in Temple City care for patients from Arcadia, San Gabriel, Pasadena, Monrovia, Monterey Park, and across the San Gabriel Valley. We accept most PPO plans (see accepted insurances), and our doctors speak English, Vietnamese, and Mandarin. Schedule an appointment or call 626-898-4560.

This article is for general education and is not a substitute for medical advice. Talk with your doctor about your own health.