Colonoscopy Procedure & Preparation | MedStar Health

Colorectal cancers are preventable through routine colonoscopies.

At MedStar Health, we make it easy to get your colonoscopy at dozens of convenient locations close to where you live and work in Washington, D.C., and Maryland. Our expert team includes specialists in gastroenterology, including board-certified physicians, advanced practice clinicians, and other providers who have sub-specialty training in detecting conditions affecting the colon and rectum.

A screening test is a procedure that is performed on a patient experiencing no gastrointestinal symptoms. It looks for evidence of colon or rectal cancer in the large intestine. These cancers are often referred to as colorectal cancer when grouped together, and a colonoscopy may be used to screen for cancer or diagnose it if you have symptoms. Although there are several screening tests available to detect colorectal cancer, this type of screening is the best option because a gastroenterologist can remove any colon or rectal polyps during the procedure.

A screening can also be used to evaluate other conditions or symptoms, including:

Many people delay colonoscopies for fear of what to expect, including how to prepare for it. But, it’s not that bad, thanks to advances over the past ten years. You may be surprised to hear that:

  • You’ll be sedated during the procedure so that you won’t feel anything
  • The procedure is short, lasting only 15 to 20 minutes
  • The drink you have to consume the day before tastes better than it used to and we have more options available for most patients

What is a colonoscopy?

A colonoscopy is a test that allows your doctor to look at the inner lining of the large intestines (colon and rectum). During your procedure, your doctor uses a thin, flexible tube (colonoscope) attached to a miniature camera. The colonoscope inserted into the rectum and colon, allowing your doctor to look for anything unusual, such as:

  • Abnormal growths, or polyps

  • Bleeding
  • Inflammation
  • Tumors
  • Ulcers

If anything suspicious is found, your doctor can collect tissue samples for further investigation, which is called a biopsy. During the procedure, your doctor can also remove any rectal/colon polyps and early colon cancers. Certain polyps are precancerous and if not removed can develop into colon cancer. By removing these polyps, your doctor can reduce your risk of developing cancer.

When should men and women get a colorectal screening via colonoscopy?

All men and women should be screened for rectal cancer and colon cancer beginning at age 45 if they are considered to have an average risk. Being at an average risk means that you do not have:

  • A personal history of these types of cancers or previously diagnosed polyps
  • A family history of these types of cancers
  • A confirmed hereditary condition that makes you more likely to develop colorectal cancer
  • Related health conditions, such as Crohn’s disease or ulcerative colitis

People with an average risk should continue screenings every ten years through the age of 75 if their screening colonoscopies do not find any precancerous polyps. According to the American Cancer Society, you and your doctor should determine whether or not to continue screening starting at age 76 and beyond.

You may be at a higher risk and need to be screened earlier than the age of 45 if you have the following risk factors:

  • A personal or family history of polyps or colorectal cancer
  • A medical history of inflammatory bowel disease (including Crohn’s disease or ulcerative colitis)
  • An inherited gene that makes you more likely to develop colorectal cancer

If you meet any of these criteria, talk to your MedStar Health gastroenterologist or primary care provider about when and how you should be screened.

Am I eligible?

Regular screening is your best chance of preventing colorectal cancer or finding it at an early and treatable stage. Take a five-minute assessment to determine if you are eligible to get screened.

Baltimore residents may be eligible for a free screening

If you are uninsured or underinsured, you may qualify for a free colorectal cancer screening at MedStar Health if you are:

  • A Baltimore City, Baltimore County, or Anne Arundel County resident
  • Age 50 or older
  • Under 50 with symptoms or a family history of colon cancer
  • Living on a limited income

Call us today at 410-350-8216 or 410-350-3444 (Spanish) to find out if you qualify for a free colorectal cancer screening in Baltimore.

What to expect

Preparing is just as important as the actual procedure because it impacts how well your doctor can see your colon and rectum. Many patients are worried about the bowel preparation process but thankfully advancements make it easier for patients. Knowing what to expect can help minimize any inconvenience or concern. Our team will provide you with thorough instructions for your bowel prep so you will know exactly what to expect and how to prepare.

Tips: How to prepare for a colonoscopy

Before this test, you will need to clean out your colon so that your doctor can safely perform the procedure. Bowel preparation can take one to two days, depending on which type of prep your doctor recommends. Plan to stay home during your prep since you will need to use the bathroom often. In addition to medications to clean the colon, you’ll have to be on a limited diet of just liquids (called a ‘clear liquid diet’) on the day before your procedure.

Here’s what to do the day before your procedure:

  • Only drink clear liquids the entire day

    Avoid eating solid food during or after prep. Instead, consume clear liquids such as:

    • Water
    • Bouillon
    • Clear sodas, like Sprite or ginger-ale
    • Pulp free lemonade
    • Coffee or tea (without milk or creamers)
    • Plain Jell-O (Avoid red, purple, or blue Jell-O, added fruit, or toppings)
  • Prepare your medication

    You will be given laxative medication ahead of time. Mix the laxative as instructed based on the type of prep selected by your gastroenterologist. Some preps can be mixed with flavor packets to help improve the taste and keeping the liquid cold can help as well.

    The standard of care is for your bowel prep to be taken in two dosages (compared to the older ‘single dose’ bowel prep). This means each dose is smaller than prior preps. Starting the evening before your procedure, you can anticipate the following:

    • After your day of clear liquids, begin drinking the solution at approximately 5 p.m. the day before your procedure.
    • Depending on your bowel prep, you will either need to drink laxative mixed with water or sports drink or a low volume bowel prep followed by a large volume of water. Follow your bowel prep instructions carefully but expect to drink an eight ounce glass every five-to-ten minutes until you consume the full volume. It also helps to drink additional water during this time to stay hydrated.
    • After you finish this half dose, you can drink water until you go to sleep or up until midnight.
    • After midnight, you should not have anything else to eat or drink.
    • Early in the morning, you will have the second half of your bowel prep. You should start drinking this five hours before your procedure and finish it no later than four hours before your procedure. It should be the same volume as the night dose so you will be familiar with the process for the morning dose.
    • After the bowel prep, you’ll go to the bathroom frequently but this whole process should be finished with enough time to get to your appointment on time.
  • No eating OR drinking prior to the exam

    Besides your morning dose of bowel prep, you are still NOT eating or drinking on the day of your procedure until after the procedure is completed. You should review your medications with your primary care doctor in advance of your procedure to determine which ones need to be taken that morning. You can take approved medications with a sip of water, even when you are not supposed to be eating.

  • If you have diabetes/take insulin

    If you have diabetes/take insulin, make sure you talk to your primary care doctor to determine how to adjust these medications as you’ll be eating less during your bowel prep and on the day of your procedure.

  • Talk to your doctor

    Talk to your doctor if you are on blood-thinning medicines (i.e., Coumadin, Heparin, Lovenox, Plavix, etc.). These often need to be stopped to safely perform a colonoscopy. You will need instructions on exactly when to stop these medications.

The day of your procedure

You’ve completed prep early in the morning on the day of your procedure and are ready for your screening. Here’s what to do next.

  • Remember, have nothing else to eat or drink until your procedure is complete (except for approved medications)
  • Avoid eating hard candy or chewing gum.
  • Wear comfortable clothing that is easy to remove.
  • Leave jewelry at home.
  • Bring a list of your current medications and allergies.
  • If you are over age 50 and have recently had an electrocardiogram (EKG), bring a copy of the EKG tracing with you or have your primary physician fax a copy.
  • Registration:

    Plan to arrive 90 minutes before our appointment time to complete check-in for your procedure.

  • Getting ready:

    Once registered, you will be asked to put on a hospital gown. A nurse will review your medical history and start an intravenous line (IV), which will be used to administer medications that will keep you sedated during the exam.

  • During the procedure:

    The procedure will only last 15 to 20 minutes. You will be sedated so that you will be comfortable. Your care team will monitor your heart rate, blood pressure, and oxygen levels the entire time

What happens after the procedure?

Once the procedure is completed, you'll wake up in the recovery room. Our nurses will monitor your vital signs, and your doctor will come in to share your results. They'll let you know if any polyps were found and removed. They'll also recommend when you should have your next colonoscopy. You can eat solid food and as long as everything is okay, you'll be ready to go home after 15 to 20 minutes.

It's normal to feel a little groggy after the procedure, so patients are required to have someone to transport them home. You may also have mild abdominal pain and mild cramping, but this should pass in a few hours. Your bowel movements may be less frequent for a few days after. This is normal since you’ve just emptied them completely for your procedure. Most patients are ready to return to work and normal activities within 24 hours after the procedure

Frequently asked questions

  • Why is bowel prep important?

    The goal of a colonoscopy is for your doctor to view the entire colon and rectum. By following the bowel prep instructions, you adequately empty your bowel, giving your doctor the best chance of spotting polyps or any abnormal tissue. If you stick to the dietary guidelines and your doctor gets an unobstructed view, you won't need another procedure for years, provided that you don't have any signs of cancer. The colonoscope can clean up small amounts of stool but the bowel prep is the key to getting good views (and finding even the smallest polyps).

  • How can I make bowel prep easier?

    Fortunately, the laxative medication that you need to drink before tastes better than it used to. Some patients report that it's easier to drink if it is chilled, poured into a cup, or consumed with a straw. It may also be helpful to create a comfortable environment in the bathroom since you'll spend more time there than usual. Stock up on high-quality toilet paper and wipes, and bring a book or crossword puzzle with you to stay distracted.

    There are many options available and if you have a specific limitation (certain textures, tastes, preference for liquids versus pills), our gastroenterologists can likely find a bowel prep that will work well for you.

  • Does the procedure hurt?

    Patients are often sedated so that they do not experience any discomfort during the procedure. Even without sedation, it causes only minimal discomfort and some patients are able to complete the procedure without sedation, when needed. The most common symptom patients may experience is bloating and cramps when they wake up from the anesthesia. Any mild discomfort is temporary and worth the lifesaving benefit of knowing you're cancer-free.

  • Do I need a colonoscopy if I don't have any rectal or colon cancer symptoms?

    Yes, even if you don't have any signs of cancer, providers recommend getting screened as a precaution. Many cancers do not have symptoms until they are more advanced and have spread. Getting screened when you don't have any symptoms and at the appropriate age is the best way to find and prevent cancer in its earliest stages or to remove precancerous polyps.  Additionally, compared to other forms of screening, a colonoscopy is the only test that allows the gastroenterologist to find and remove polyps (and potentially early forms of colon cancer) during the screening exam.

  • Are there other ways to screen for colorectal cancer?

    Yes, there are several tests available to screen for cancer in the colon or rectum, including a fecal occult blood test (FOBT), at-home kits that analyze stool samples, and sigmoidoscopy, which uses a flexible, lighted tube to view the inside of the rectum and colon. A virtual colonoscopy is also an option for colon cancer screening, especially for patients who cannot have standard colonoscopies. Virtual colonoscopies use low-dose computed tomography (CT) imaging to examine the colon for polyps. It's less invasive and doesn't require anesthesia. Virtual tests require repeat screenings more frequently than a traditional procedure.

    A colonoscopy is the only test that allows your doctor to remove polyps, if found. As a result, it is the best available test to identify and prevent colon cancer. We strongly recommend a test for colon cancer screening in all appropriate patients. If you are still wondering if a colonoscopy is right for you, a MedStar Health gastroenterologist can help you weigh the pros and cons.

Looking for expert cancer care?

With multiple locations throughout the region, patients have access to many of the nation’s renowned cancer specialists offering high quality care, second opinions and a chance for better outcomes close to where they live and work. Georgetown Lombardi Comprehensive Cancer Center, one of the nation’s comprehensive cancer centers designated by the National Cancer Institute (NCI), serves as the research engine allowing patients access to clinical trials that often lead to breakthroughs in cancer care.

Our locations

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MedStar Georgetown Cancer Institute at MedStar St. Mary’s Hospital

25500 Point Lookout Rd.
First Fl.
Leonardtown, MD 20650

MedStar Health: Gastroenterology at MedStar Harbor Hospital

3001 South Hanover St.
Outpatient Center
Suites 203 and 300
Baltimore, MD 21225

MedStar Health: Gastroenterology at Silver Spring

12012 Veirs Mill Rd.
Silver Spring, MD 20906


MedStar Health: Gastroenterology at Lutherville

1300-B Bellona Ave.
Lutherville-Timonium, MD 21093

MedStar Health: Gastroenterology at MedStar Georgetown University Hospital

3800 Reservoir Road, NW
Main Hospital Building, Second Floor
Room M2210
Washington, DC 20007

MedStar Health: Gastroenterology at MedStar Good Samaritan Hospital

5601 Loch Raven Blvd.
Russell Morgan Bldg.
3rd Floor
Baltimore, MD 21239

MedStar Health: Gastroenterology at MedStar Union Memorial Hospital

3304 Guildford Ave.
Baurenschmidt Bldg., 2nd Fl.,
Suite 265
Baltimore, MD 21218

MedStar Health: Gastroenterology at MedStar Washington Hospital Center

106 Irving St., NW
POB S Suite 205
Washington, DC 20010

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