Gateway Gastroenterology: Services, Doctors, Conditions, Procedures, Locations, and What Patients Should Know

28 Aug Gateway Gastroenterology: Services, Doctors, Conditions, Procedures, Locations, and What Patients Should Know

Gateway Gastroenterology is a gastroenterology and hepatology practice based in Chesterfield, Missouri, serving patients who need care for digestive system and liver conditions. The practice provides evaluation, diagnosis, treatment, preventive care, and several diagnostic procedures for gastrointestinal problems.

For people searching for Gateway Gastroenterology, one important point is that the name may be confused with other medical facilities or gastroenterology centers that use the word “Gateway.” This article focuses on Gateway Gastroenterology in Chesterfield, Missouri, whose main office is located on North Outer 40 Road.

The practice describes its team as including board-certified gastroenterologists and advanced nurse practitioners. Its services cover common digestive concerns such as acid reflux, irritable bowel syndrome, inflammatory bowel disease, and liver disease, along with screening and diagnostic procedures such as colonoscopy, upper endoscopy, capsule endoscopy, breath testing, and FibroScan.

This guide explains what Gateway Gastroenterology offers, what a gastroenterologist does, which symptoms may require a specialist, what to expect from common procedures, and how patients can prepare for an appointment.

What Is Gateway Gastroenterology?

Gateway Gastroenterology is a medical practice specializing in gastroenterology and hepatology. Gastroenterology is the branch of medicine focused on the digestive system. Hepatology focuses more specifically on the liver and related conditions.

The digestive system includes much more than the stomach. It includes the esophagus, stomach, small intestine, large intestine, rectum, and anus. Gastroenterologists also evaluate problems involving organs such as the liver, gallbladder, pancreas, and bile ducts.

Gateway Gastroenterology states that its physicians treat a broad range of gastrointestinal conditions and that patients receive care from a dedicated gastroenterologist. The practice emphasizes communication and continuity of care rather than treating every visit as an isolated appointment.

This approach can be especially useful for people with chronic digestive conditions. Problems such as inflammatory bowel disease, chronic reflux, liver disease, or recurring abdominal symptoms may require several appointments, laboratory tests, imaging studies, medication changes, and follow-up procedures.

A gastroenterology practice can bring many of these services together so patients do not have to manage every part of their digestive health separately.

Where Is Gateway Gastroenterology Located?

The main Gateway Gastroenterology office is located at 17298 N. Outer 40 Road, Suite 200, Chesterfield, Missouri 63005. The practice lists its main office phone number as 314-529-4900. Its regular office hours are Monday through Friday from 8:00 AM to 4:00 PM.

The practice also performs procedures at several locations. These include Gateway Endoscopy Center, St. Luke’s Hospital GI Lab, and St. Louis Multi-Specialty Surgery Center.

This distinction is important because a patient’s consultation may happen at the main office while a colonoscopy or another procedure may be performed at a separate facility.

Patients should confirm the exact location listed for their appointment before traveling, particularly when the visit involves an endoscopy or other procedure.

What Does a Gastroenterologist Do?

A gastroenterologist is a physician trained to diagnose and manage diseases involving the digestive system and liver.

A primary care doctor may initially evaluate symptoms such as stomach pain, heartburn, constipation, diarrhea, nausea, or changes in bowel habits. If symptoms continue, become more complicated, or suggest a condition requiring specialized testing, the patient may be referred to a gastroenterologist.

A gastroenterologist may:

• Review digestive symptoms and medical history
• Perform a physical examination
• Order blood or stool tests
• Evaluate abnormal liver tests
• Investigate unexplained abdominal pain
• Diagnose reflux and other digestive disorders
• Treat inflammatory bowel disease
• Evaluate gastrointestinal bleeding
• Perform colonoscopy
• Perform upper endoscopy
• Perform certain specialized diagnostic tests
• Monitor liver disease
• Provide colorectal cancer screening
• Remove certain polyps during colonoscopy
• Take tissue samples for laboratory examination

Gastroenterologists also help patients understand when symptoms can be managed conservatively and when additional testing is necessary.

This is an important part of good digestive care. Not every stomach symptom requires an invasive test, but persistent or concerning symptoms should not automatically be ignored.

Conditions Treated by Gateway Gastroenterology

Gateway Gastroenterology lists a wide range of gastrointestinal and liver conditions among the problems its specialists evaluate and treat.

Acid Reflux and GERD

Acid reflux happens when stomach contents move upward into the esophagus. Some people experience occasional heartburn, while others have gastroesophageal reflux disease, commonly called GERD.

Symptoms can include:

• Burning in the chest
• Sour or bitter taste
• Regurgitation
• Trouble swallowing
• Symptoms that become worse after meals
• Nighttime discomfort
• Chronic cough in some patients

Persistent reflux deserves attention because ongoing symptoms may affect the esophagus and quality of life.

A gastroenterologist can determine whether symptoms are consistent with reflux and whether further testing is appropriate.

Irritable Bowel Syndrome

Irritable bowel syndrome, or IBS, is a common digestive disorder involving symptoms such as abdominal discomfort and changes in bowel habits.

People with IBS may experience constipation, diarrhea, or alternating bowel patterns.

IBS can be frustrating because symptoms may vary from one person to another. A good evaluation is important because IBS symptoms can overlap with other digestive disorders.

The goal of specialist care is not simply to give a patient a label. It is to understand the symptom pattern, consider other possible causes, and develop a practical management plan.

Inflammatory Bowel Disease

Inflammatory bowel disease, or IBD, generally refers to conditions such as Crohn’s disease and ulcerative colitis.

These conditions can cause:

• Abdominal pain
• Diarrhea
• Blood in the stool
• Weight changes
• Fatigue
• Urgent bowel movements

IBD can require long-term monitoring. Treatment may include medications, laboratory testing, endoscopic evaluation, nutritional guidance, and coordination with other healthcare professionals.

Gateway Gastroenterology’s team includes physicians with gastroenterology and hepatology training, and the practice specifically lists inflammatory bowel disease among the conditions it treats.

Liver Disease

Gastroenterology and hepatology overlap because the liver plays a major role in digestion and metabolism.

Patients may be referred to a gastroenterologist for abnormal liver blood tests, fatty liver disease, hepatitis, cirrhosis, or other liver concerns.

A liver condition can sometimes exist without obvious symptoms. That is why abnormal laboratory results should be discussed with a healthcare professional even when a person feels well.

Abdominal Pain

Abdominal pain has many possible causes.

Pain may come from the stomach, intestines, gallbladder, pancreas, liver, urinary system, abdominal muscles, or other structures.

The location, timing, severity, duration, and associated symptoms can help a physician narrow down possible causes.

For example, abdominal pain associated with persistent vomiting, fever, gastrointestinal bleeding, jaundice, or unexplained weight loss may require more urgent evaluation.

A gastroenterologist can determine which tests, if any, may be appropriate.

Gastrointestinal Bleeding

Blood in the stool or vomit should never be automatically dismissed.

Gastrointestinal bleeding can result from several conditions, including ulcers, hemorrhoids, polyps, inflammatory disorders, or other problems.

The appearance of blood can provide clues, but only medical evaluation can determine the underlying cause.

Severe bleeding, fainting, weakness, rapid heartbeat, or other signs of significant blood loss may require emergency medical attention rather than a routine office appointment.

Colon Cancer Screening at Gateway Gastroenterology

Colon cancer screening is one of the most important preventive services provided by gastroenterology practices.

Gateway Gastroenterology specifically lists colon cancer screening as one of its services.

Colorectal cancer can develop from precancerous polyps. Finding and removing certain polyps during colonoscopy can help prevent some colorectal cancers from developing.

Screening recommendations depend on factors such as age, personal history, family history, previous colonoscopy results, and other risk factors.

Many average-risk adults begin colorectal cancer screening in middle age, but the correct timing should be determined with a healthcare professional because recommendations can change based on individual circumstances.

One of the biggest mistakes people make is waiting for symptoms before thinking about colorectal cancer screening.

Screening is different from diagnostic testing. Screening is performed when someone may not have symptoms but is at an age or risk level where testing is recommended.

Colonoscopy at Gateway Gastroenterology

Colonoscopy is one of the best-known procedures performed by gastroenterologists.

During a colonoscopy, a flexible instrument with a camera is used to examine the lining of the large intestine.

A colonoscopy may be performed for screening or to investigate symptoms such as:

• Rectal bleeding
• Persistent changes in bowel habits
• Unexplained anemia
• Chronic diarrhea
• Certain types of abdominal pain
• Abnormal previous testing
• A personal or family history that increases colorectal cancer risk

One advantage of colonoscopy is that physicians can often identify and remove certain polyps during the same procedure.

Gateway Gastroenterology lists colonoscopy among its services and performs procedures at several affiliated procedure locations.

What Happens Before a Colonoscopy?

The preparation is often the part patients worry about most.

A clean colon is necessary because stool can block the physician’s view.

Patients generally receive detailed instructions about diet, bowel preparation, medications, and timing. The exact instructions should come from the medical team because preparation plans can vary.

Patients should not change prescription medications on their own before a procedure.

Certain medicines, including some blood thinners and diabetes medications, may require special instructions.

What Happens During a Colonoscopy?

Patients are generally given medication to help them remain comfortable during the procedure.

The physician carefully examines the colon and may remove polyps or collect tissue samples if necessary.

The procedure itself may not take very long, but patients should plan for additional time because of preparation, recovery, and discharge instructions.

Because sedation can affect alertness, patients should follow the facility’s instructions about transportation and activities after the procedure.

Upper Endoscopy at Gateway Gastroenterology

Upper endoscopy, also called esophagogastroduodenoscopy or EGD, allows a gastroenterologist to examine the upper digestive tract.

This includes the:

• Esophagus
• Stomach
• First part of the small intestine

Gateway Gastroenterology lists upper endoscopy as one of its available services.

An upper endoscopy may help evaluate symptoms such as persistent upper abdominal discomfort, difficulty swallowing, unexplained anemia, bleeding, chronic reflux symptoms, nausea, or other concerns.

The physician may take small tissue samples during the procedure. Patients typically do not feel the biopsy itself.

Double or Bi-Directional Endoscopy

Gateway Gastroenterology also lists double, or bi-directional, endoscopy among its services.

This generally refers to evaluating both the upper and lower digestive tract, commonly through upper endoscopy and colonoscopy.

A combined procedure can sometimes be useful when symptoms or test results raise questions involving more than one part of the digestive tract.

The benefit is that both areas can be evaluated during one planned procedural session rather than requiring completely separate visits.

Whether this approach is appropriate depends on the patient’s symptoms, medical history, risk factors, and physician recommendation.

Capsule Endoscopy

Capsule endoscopy is another service listed by Gateway Gastroenterology.

Instead of using a traditional endoscope for the entire examination, the patient swallows a small capsule containing a camera. As the capsule moves through the digestive tract, it captures images.

Capsule endoscopy can be particularly useful for examining parts of the small intestine that are difficult to reach with standard upper endoscopy and colonoscopy.

It is a specialized test and is not necessary for every digestive complaint.

The physician decides whether it is appropriate based on the clinical situation and other test results.

Breath Testing for Digestive Problems

Gateway Gastroenterology offers hydrogen and methane breath testing as well as lactose and fructose intolerance testing.

Breath tests can provide useful information about how the digestive system processes certain carbohydrates and how gases are produced during digestion.

For patients with unexplained bloating, gas, diarrhea, or other digestive symptoms, a breath test may sometimes help investigate specific causes.

However, breath testing should be interpreted in the context of the entire medical history.

A test result by itself does not always explain every digestive symptom.

This is an important distinction because patients can become frustrated when they expect one test to provide a complete answer. Digestive health is complex, and good diagnosis often involves combining symptoms, examination findings, laboratory results, and testing.

FibroScan and Liver Evaluation

FibroScan is another service listed by Gateway Gastroenterology.

FibroScan is a noninvasive technology used to assess liver stiffness and fat-related changes.

For patients with certain liver conditions, this type of assessment can provide useful information without requiring a traditional liver biopsy.

Liver evaluation may be especially important when someone has abnormal liver enzymes, known liver disease, metabolic risk factors, or other findings that raise concern about liver health.

The correct testing strategy depends on the individual patient.

Infusion Services

Gateway Gastroenterology also lists infusion services among its offerings.

Infusion treatment can be used for certain medical therapies that need to be administered directly into a vein.

In gastroenterology, infusion-based medications may be used for some patients with chronic inflammatory conditions or other diseases when the physician determines that this form of treatment is appropriate.

Infusion therapy requires careful medical supervision, including appropriate medication selection and monitoring.

Who Are the Doctors at Gateway Gastroenterology?

Gateway Gastroenterology’s current provider page lists several gastroenterologists and advanced practice providers.

The listed physicians include Taylor Geisman, MD; Jeffrey Mathews, MD; Brian McMorrow, MD; Rajeev Ramgopal, MD; Richard Riegel, MD; Siri Ancha, MD; Tim Brotherton, MD; Jason Haas, DO; and Christopher Nguyen, DO. The practice also lists gastroenterology nurse practitioners Cheri Carmody, ANP; Kaitlin Schild, AGNP; and Sarah Keim, FNP.

Provider availability can change, so patients should use the practice’s current provider information when deciding whom to contact.

Taylor Geisman, MD

Taylor Geisman, MD, is listed as a board-certified gastroenterologist. Her background includes medical training at Washington University in St. Louis and specialty training in gastroenterology and hepatology at Barnes-Jewish Hospital. The practice notes that she has research experience in inflammatory bowel disease while maintaining a general gastroenterology and hepatology practice.

Brian McMorrow, MD

Brian McMorrow, MD, is listed as a board-certified gastroenterologist with expertise in gastroenterology and hepatology. According to his Gateway profile, he completed medical school and internal medicine residency training at Saint Louis University and is a member of professional gastroenterology organizations.

Jason Haas, DO

Jason Haas, DO, is listed as a board-certified gastroenterologist. His profile states that he completed gastroenterology fellowship training at Aurora Health Care and previously practiced in Springfield, Missouri.

The broader provider team gives patients access to physicians and advanced practice clinicians working within the same gastroenterology-focused practice.

What Should You Bring to a Gateway Gastroenterology Appointment?

A specialist appointment is more useful when the patient arrives prepared.

Consider bringing:

• A list of current medications
• Vitamins and supplements
• Known medication allergies
• Previous digestive testing results
• Previous colonoscopy or endoscopy reports
• Relevant imaging reports
• A family history of gastrointestinal disease or colorectal cancer
• A list of current symptoms
• Questions you want answered

It can also help to write down when symptoms started.

For digestive problems, timing matters. A doctor may ask whether symptoms occur before meals, after meals, at night, during stressful periods, or after specific foods.

A symptom diary can sometimes make patterns easier to identify.

Questions to Ask a Gastroenterologist

Patients should feel comfortable asking questions.

Useful questions include:

What could be causing my symptoms?

Do I need testing?

What are the benefits and risks of the recommended test?

Are there alternatives to this procedure?

How should I prepare?

Will I need sedation?

When should I expect results?

What symptoms should make me call the office?

What can I do at home to improve my symptoms?

If medication is recommended, ask how long it should be taken and what side effects should be reported.

These questions help patients participate actively in their care.

How to Prepare for a Gastroenterology Procedure

Preparation depends on the procedure.

For a colonoscopy, bowel preparation is essential.

For an upper endoscopy, patients may need to avoid food and liquids for a specified period before the procedure.

For breath testing, dietary restrictions may apply before the test.

For infusion treatment, the medical team may provide instructions about medications and other health concerns.

Patients should follow the instructions provided by the facility rather than relying on general advice found online.

If instructions are unclear, contacting the medical office before the appointment is usually the safest approach.

Insurance and Payment at Gateway Gastroenterology

Gateway Gastroenterology states that it is in-network with many insurance plans, while also advising patients to confirm network status directly with their insurance company.

This is important because insurance coverage can depend on the specific plan.

Being “in network” with an insurance company does not necessarily mean every service, procedure, facility, physician, anesthesia service, laboratory charge, or pathology charge will be covered in the same way.

Before a major procedure, patients may want to ask:

Is the physician in network?

Is the procedure facility in network?

Is anesthesia covered?

Will pathology charges apply?

Is prior authorization required?

What deductible or coinsurance applies?

Patients should also confirm whether their specific insurance plan is accepted because insurance participation can change.

Gateway Gastroenterology Locations and Procedure Centers

The main Gateway Gastroenterology office is in Chesterfield, Missouri.

The practice also identifies Gateway Endoscopy Center at 17298 N. Outer 40 Road, Suite 100, Chesterfield. It lists St. Luke’s Hospital GI Lab at 232 S. Woods Mill Road, Suite 130, Chesterfield, and St. Louis Multi-Specialty Surgery Center at 884 Woods Mill Road, Suite 100, Ballwin.

These different locations are important because patients should not assume that every appointment takes place at the main office.

The practice’s official contact information should be checked before a visit because office locations, hours, and procedure arrangements may change.

What Makes a Good Gastroenterology Practice?

When choosing a gastroenterology practice, patients often focus only on online ratings.

Ratings can be useful, but they are not enough to judge medical quality.

A better approach is to consider several factors:

The physicians’ training and board certification matter.

The range of services matters.

The ability to provide appropriate diagnostic testing matters.

Communication matters.

Continuity of care matters.

Procedure safety and proper follow-up matter.

The practice’s ability to coordinate care with other physicians can also be valuable.

Gateway Gastroenterology says its physicians and advanced nurse practitioners focus on approachable communication and continuity, with each patient cared for by a dedicated gastroenterologist.

For a patient with a long-term digestive condition, this continuity may be particularly helpful.

When Should You See a Gastroenterologist?

Not every stomach problem requires a specialist.

Temporary indigestion after an unusually large meal, for example, may not require a gastroenterology appointment.

However, persistent or recurring symptoms deserve more attention.

Consider discussing a referral with a healthcare professional if you experience:

• Ongoing abdominal pain
• Persistent heartburn
• Difficulty swallowing
• Repeated vomiting
• Long-lasting diarrhea
• Chronic constipation
• Unexplained weight loss
• Blood in the stool
• Black or tar-like stool
• Persistent bloating
• Unexplained anemia
• Abnormal liver tests
• A strong family history of colorectal cancer
• A need for colorectal cancer screening
• A previously diagnosed digestive disease that requires specialist monitoring

The specific urgency depends on the symptoms.

Symptoms That May Require Urgent Medical Care

A routine gastroenterology appointment is not always the correct next step.

Seek urgent medical attention for severe or rapidly worsening abdominal pain, significant gastrointestinal bleeding, fainting, severe weakness, persistent vomiting with inability to keep fluids down, severe dehydration, or other serious symptoms.

Yellowing of the skin or eyes, particularly when combined with abdominal pain, fever, confusion, or significant illness, also deserves prompt medical evaluation.

The goal of a specialist appointment is planned medical care. Emergency symptoms may require an emergency department or urgent medical evaluation instead.

Gateway Gastroenterology and Preventive Digestive Health

One of the most useful ways to think about gastroenterology is not simply as treatment for people who are already sick.

Gastroenterology also has an important preventive role.

Colorectal cancer screening is a major example.

Early identification of certain precancerous changes can provide an opportunity for treatment before cancer develops.

Preventive digestive care can also include evaluating risk factors, monitoring liver health, managing chronic conditions, and helping patients understand symptoms before they become more disruptive.

This preventive mindset is especially valuable because some gastrointestinal diseases can progress quietly.

How Patients Can Improve Digestive Health

Specialist care is important, but everyday habits also influence digestive health.

A balanced diet with adequate fiber can support regular bowel movements for many people.

Drinking enough fluids is also important.

Regular physical activity supports overall health and can benefit bowel regularity.

Eating slowly and paying attention to portion sizes may help some people who experience indigestion or reflux.

People with specific food intolerances may benefit from professional evaluation rather than eliminating large numbers of foods without guidance.

Sleep and stress management may also matter because the digestive system and nervous system interact closely.

However, lifestyle changes should complement medical evaluation rather than replace it when significant symptoms are present.

Common Misunderstandings About Gastroenterology

One common misunderstanding is that gastroenterologists only perform colonoscopies.

Colonoscopy is an important part of gastroenterology, but the specialty covers much more.

Gastroenterologists diagnose and treat diseases involving the esophagus, stomach, intestines, liver, pancreas, gallbladder, and related digestive structures.

Another misunderstanding is that digestive symptoms are always caused by food.

Food can influence symptoms, but persistent digestive problems may have many possible causes.

A third misconception is that someone must have severe symptoms before seeing a specialist.

Preventive screening and evaluation of persistent symptoms are important reasons for gastroenterology care.

How to Choose the Right Gastroenterologist

Choosing a gastroenterologist is a personal decision.

Start by checking whether the doctor is appropriate for your medical needs.

For example, someone with inflammatory bowel disease may want a physician experienced in managing long-term inflammatory conditions. Someone with liver concerns may want a provider with hepatology experience.

You should also consider:

• Insurance participation
• Location
• Appointment availability
• Procedure locations
• Communication style
• Follow-up process
• Access to testing
• Coordination with primary care

The best doctor is not necessarily the one with the highest online rating.

A good match is a physician who understands your medical situation, communicates clearly, and provides an appropriate treatment plan.

Gateway Gastroenterology Patient Experience

Gateway Gastroenterology emphasizes an approachable care model and says that patients should feel heard and understood.

This may sound like a simple point, but communication is especially important in gastroenterology.

Digestive symptoms can be embarrassing for some people.

Patients may hesitate to discuss bowel movements, rectal bleeding, gas, stool changes, or other sensitive symptoms.

A comfortable medical environment can make it easier for patients to describe what is really happening.

Accurate communication helps physicians make better clinical decisions.

How to Make a Gastroenterology Visit More Productive

Patients can take several simple steps before their appointment.

First, write down the main problem in one sentence.

For example:

“I have had upper abdominal discomfort after meals for three months.”

Then list the details.

When did it start?

Is it getting better or worse?

What makes it worse?

What makes it better?

Does it happen every day?

Are there bowel changes?

Have you lost weight?

Have you noticed blood?

Have you tried medication?

These details can help the physician understand the pattern more quickly.

Also bring previous test results whenever possible.

A previous colonoscopy report can be especially valuable because the timing and findings of previous examinations may influence future screening plans.

What Patients Should Know Before Booking

Before scheduling an appointment, patients should have a basic understanding of why they are seeking gastroenterology care.

If the appointment is for a new symptom, write down the symptoms and how long they have been present.

If the appointment is for screening, ask whether the visit is intended to discuss screening options or schedule a procedure.

If the appointment is for an existing condition, collect previous records and medication information.

If the visit involves a procedure, carefully review the preparation instructions.

Patients should also confirm the location.

The main office and procedure facilities are not necessarily the same place.

Final Thoughts on Gateway Gastroenterology

Gateway Gastroenterology is a gastroenterology and hepatology practice in Chesterfield, Missouri, offering care for a broad range of digestive and liver conditions. Its services extend from routine consultations and preventive colon cancer screening to procedures such as colonoscopy, upper endoscopy, capsule endoscopy, breath testing, and FibroScan.

For patients dealing with ongoing digestive symptoms, choosing a specialist should involve more than searching for a nearby office. Consider physician qualifications, the services available, communication, insurance coverage, procedure facilities, and the type of care needed.

The most important lesson is that digestive symptoms should be evaluated based on their pattern and severity. Some problems are temporary, while others require testing or long-term management. Preventive screening is also important because serious gastrointestinal conditions can sometimes develop before noticeable symptoms appear.

Gateway Gastroenterology provides a range of gastroenterology and hepatology services for patients in the St. Louis area. Anyone considering the practice should confirm current provider availability, insurance participation, appointment details, and procedure locations directly with the practice before making healthcare decisions.

Frequently Asked Questions About Gateway Gastroenterology

1. Does Gateway Gastroenterology treat children?

Gateway Gastroenterology’s listed practice information focuses on adult gastroenterology and hepatology services. Patients looking for pediatric digestive care should confirm whether a particular provider treats children or ask their primary care physician about an appropriate pediatric gastroenterology referral.

2. Can I request a specific Gateway Gastroenterology doctor?

Patients can ask about specific physicians when scheduling. Gateway Gastroenterology currently lists multiple gastroenterologists and advanced practice providers, although availability can change.

3. How long does it take to get colonoscopy results?

Some findings may be explained shortly after the procedure. However, biopsy or polyp pathology results may take additional time. The exact timing depends on the procedure and laboratory processing.

4. Can digestive problems affect mental well-being?

Yes. Long-term digestive symptoms can affect sleep, daily activities, social life, work, and overall quality of life. This does not mean digestive symptoms are “just stress.” Both physical and emotional factors can influence how digestive symptoms are experienced, so persistent symptoms deserve appropriate medical evaluation.

5. What should I do if I cannot complete my colonoscopy preparation?

Contact the medical team or procedure facility for instructions. Do not simply assume the procedure can proceed normally with an incomplete preparation. A poorly prepared colon may prevent the physician from seeing the colon clearly and may require the procedure to be repeated.