Diagnostic & Therapeutic Colonoscopy

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Hospital Affiliations

NYU Langone Hospital – Long Island

Mount Sinai Hospital, New York

Mount Sinai South Nassau

Mercy Medical Center

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What Is Diagnostic & Therapeutic Colonoscopy?

Colonoscopies are the gold standard of diagnostic testing when it comes to detecting colon cancer, and they are also used to diagnose other diseases as well, such as ulcerative colitis (UC). The  American Cancer Society, US Preventive Services Task Force, and US  Mutli-Society Task Force on Colorectal Cancer have all recommended that both men and women should start screening for colorectal cancer at age 45. This is a reduction from the former recommendation of age 50. There are three types of colonoscopy—screening, diagnostic, and therapeutic. However, there are differences between the three types of colonoscopy. 

What Is a Screening Colonoscopy?

If you are scheduling your very first colonoscopy as part of a preventive measure (e.g., you just turned 45 and got a referral from your primary care physician). This is also called a screening colonoscopy. Your physician will schedule a screening colonoscopy if you are asymptomatic (have no symptoms), You are also a candidate for a screening colonoscopy if you have no personal history of polyps or colon cancer, have no conditions such as inflammatory bowel disease (IBD), and there is no family history that would indicate colon cancer, polyps, or other gastrointestinal conditions.  You may also schedule a screening colonoscopy if you have an immediate family history of polyps, colon cancer, or if you have a personal history of colorectal cancer. A screening colonoscopy is similar to mammograms and other procedures, as it is a preventative measure for early detection of polyps or colon cancer. 

What Is a Diagnostic Colonoscopy?

A diagnostic colonoscopy is scheduled for someone at a higher risk of contracting colon cancer or other gastrointestinal problems. If your healthcare provider orders a diagnostic colonoscopy, there may already be indicators that there is an issue. You may be presented to your doctor with symptoms such as blood in the stool, changes in bowel movements, long-term constipation or diarrhea, abdominal pain, or anemia. These are all markers of several different gastrointestinal disorders, from Crohn’s disease to colorectal cancer. Therefore, your gastroenterologist will schedule you for a diagnostic colonoscopy. 

What Is a Therapeutic Colonoscopy?

A therapeutic colonoscopy is one where your physician takes action during the procedure to correct a disorder, such as removing a polyp, stopping bleeding, or dilating (stretching) a narrowed area called a stricture. Therapeutic colonoscopies can often start out as a diagnostic exam. When your physician identifies a disorder during the diagnostic colonoscopy and feels it can be corrected during the procedure, he/she can perform the appropriate therapy.

What are the Differences Between Screening, Diagnostic and Therapeutic Colonoscopy?

There is no difference in how the test is performed regarding screening, diagnostic and therapeutic colonoscopies. How colonoscopies are classified is important when it comes to billing your insurance. For example, Medicare and most private insurance will cover your first screening colonoscopy in full. However, sometimes patients have to pay a copay or deductible when they have a therapeutic or diagnostic colonoscopy. A good rule of thumb before you schedule any colonoscopy is to confirm with your insurance company. 

What Happens During a Colonoscopy?

Colonoscopies do require some preparation so that your intestines are clear for the doctor to examine. A few days before your colonoscopy, you’ll switch to a liquid diet. Typically, the night before your procedure, you will ingest a solution that will clear and empty your bowels. It depends on your gastroenterologist—sometimes this part of the prep is done the night before, while others may be in two parts. 

Patients are often wary of the bowel prep and the procedure, but the prep occurs relatively quickly, and you will be under sedation during the colonoscopy, so there is no pain or discomfort. It is an outpatient procedure, and most often, you can resume normal activities the next day or soon after. Your doctor will instruct you on your diet immediately after colonoscopy. 

During the procedure, the physician will use a colonoscope, which is inserted into the anus and reaches the end of the colon. It is a long, thin, and flexible tube that has a small camera attached to it. Using the colonoscope, the doctor can see if there are any visible problems with the colon or rectum, such as polyps. 

A wonderful thing about colonoscopy is that it can both diagnose and remove polyps at the same time. If you have benign or cancerous polyps in your colon, the physician can remove them during the procedure. Depending on your potential diagnosis, your gastroenterologist may take a biopsy to have the tissue evaluated. 

What Types of Diseases Does a Colonoscopy Detect?

Colonoscopy is often linked with colon cancer, as it is the gold standard for early detection of and best means of preventing colon cancer. However, there are other diseases and disorders that your physician may find during the procedure. Both diagnostic and therapeutic procedures can discover:

  • Polyps (which are the precursor to colorectal cancer)
  • Crohn’s disease
  • Cancerous tissue (cancer does not always present as polyps)
  • Diverticulitis
  • Diverticulosis
  • Ulcerative colitis
  • Hemorrhoids 

Depending on each individual patient, a gastroenterologist may also order upper endoscopy. It is a similar test, except a thin tube is inserted into the throat to evaluate the esophagus, abdomen, and small intestine. Upper endoscopies can often detect conditions such as gastric cancer, hiatal hernia, acid reflux disease, Barrett’s esophagus, and ulcers.