What is colonoscopy test? Why & How it is done | oncology

Colonoscopy test

What is a colonoscopy test?

A colonoscopy is a test and it is used to detect changes or abnormalities in the large intestine (colon) and rectum. During a colonoscopy test, your doctor will look for abnormalities or diseases in your large intestine, especially the colon. They use colonoscopy, a thin, flexible tube that connects the light and the camera. The colon helps form the lowest part of the gastrointestinal tract. It consumes food, absorbs nutrients, and eliminates waste.

The colon joins the anus through the rectum. The anus is the expulsion of faeces into your body. During the colonoscopy test, your doctor may also take tissue samples for a biopsy or remove abnormal tissue such as polyps. If necessary, polyps or other types of abnormal tissue can be removed with an endoscope during the colonoscopy. Tissue samples (biopsies) may also be taken during the colonoscopy test.

Why the test is done?

Your doctor may recommend a colonoscopy to:

  • Investigate intestinal signs and symptoms. Colonoscopy test can help your doctor diagnose the causes of abdominal pain, rectal bleeding, chronic constipation, chronic diarrhoea, and other intestinal problems.
  • Colon cancer screening. If you are 50 years old and at risk for colon cancer (you have no colon cancer risk other than age), your doctor may recommend colon cancer every 10 years or sometimes get a colon cancer test. A colonoscopy is an option for the detection of colon cancer. Talk to your doctor about your options.
  • Look for more polyps. If you have had polyps before, your doctor may recommend a follow-up colonoscopy to look for and remove any additional polyp. This is done to reduce the risk of colon cancer.

Colonoscopy test can be used to screen for colon cancer and other problems. Screening tests can help your doctor:

  • Look for signs of cancer and other problems.
  • Explore the cause of unexplained changes in bowel habits
  • Evaluate symptoms of abdominal pain or bleeding.
  • Find the cause of unexplained weight loss, chronic constipation, or diarrhoea
  • The American College of Surgeons estimates that 90 percent of polyps or tumors can be detected by colonoscopy.

What should I do before a colonoscopy test?

Before your colonoscopy test, tell your doctor about any specific medical conditions you may have, including:

  • The pregnancy
  • Ung lung diseases
  • Heart disease
  • Allergic to any medication

If you have diabetes or are taking medicines that affect blood clotting; Adjustments to these medications may be required before the colonoscopy. Never stop taking the medicine without first checking with your doctor.

You will need to take antibiotics before your colonoscopy test

Having an artificial heart valve

It has always been said that it is necessary to take antibiotics before a dental or surgical procedure.

How often should a colonoscopy test be done?

The American College of Physicians recommends a colonoscopy every 10 years for people who meet all of the following criteria:

  • 50 to 75 years
  • The average risk of colorectal cancer
  • It must have a useful life of at least 10 years.

The British Journal of Medicine (BMJ) recommends a one-time colonoscopy for people who meet all of these criteria:

  • 50 to 79 years
  • The average risk of colorectal cancer
  • The risk of colorectal cancer is at least 3 percent in 15 years.

If you are at increased risk for colon cancer, you may need more frequent procedures. According to the American Cancer Society (ACS), the people who need to be tested every 1 to 5 years are:

  • People who had polyps removed during a previous colonoscopy
  • People with a pre-existing history of colon cancer
  • People with a family history of colon cancer
  • People with inflammatory bowel disease (IBD)

What are the risks of a colonoscopy?

Since colonoscopy is a simple procedure, there are generally some permanent effects on this test. In most cases, the benefits of diagnosing and initiating treatment far outweigh the benefits of colonoscopy.

However, some rare problems:

  • Bleeding from the biopsy site if a biopsy occurs
  • Adverse reaction to the use of a sedative.
  • A tear in the rectal wall or colon

A procedure called a virtual colonoscopy uses CT scans or MRIs to take pictures of your colon. By choosing this instead, you can avoid some of the problems associated with traditional colonoscopy However, it has its own drawbacks. For example, it may not detect very small polyps. As with new technology, you are less likely to be covered by health insurance.

Preparation for a colonoscopy test

Before your colonoscopy, you must clean (empty) your colon. Any remnants in your colon can cloud your view of your colon and rectum during the test. To empty your colon, your doctor may ask you:

  • Follow a special diet the day before the test. Generally, you should not eat solid food the day before the test. Drinks can be limited to clear liquids: plain water, tea, and coffee that do not contain milk or cream, broth, and carbonated drinks. Stay away from red fluids, which can be mistaken for blood during colonoscopy. You cannot eat or drink anything after midnight before the test.
  • Take laxative. Your doctor will usually recommend taking a laxative in pill or liquid form. You may be instructed to take the laxative the night before your colonoscopy, or you may be asked to use the laxative both the night before and the morning of the procedure.
  • Use the enema kit. In some cases, you may need to use an over-the-counter enema kit the night before the test or a few hours before the test to empty your colon. It is usually only effective for emptying the lower colon and is generally not recommended as the primary way to empty the colon.
  • Adjust your medication. Remind your doctor about the medications you take at least a week before the test, especially if you have diabetes, high blood pressure, or heart problems, or if you are taking medications or medications that contain iron.

Also tell your doctor if you are taking anticoagulant aspirin or other medications, warfarin (Common, Zantoven); New anticoagulants such as dabigatran (Pradaxa) or rivaroxaban (Xarelto) used to reduce the risk of blood spot clotting or stroke, Or heart medications that affect platelets such as clopidogrel (Plavix). You may need to adjust your dose or temporarily stop taking the medicine. The colonoscopy generally takes 30 to 60 minutes.

What happens during the colonoscopy?

The colonoscopy test is done by an experienced doctor and takes about 30 to 60 minutes. Medicines are given into a vein to make you feel venous and drowsy. You will be asked to lie on your left side of the exam table. During the colonoscopy, the doctor uses a colonoscopy, a long, flexible tubular device about 1/2 inch in diameter that transmits an image of the lining of the colon so that the doctor can examine it for abnormalities. The colonoscope is inserted through the rectum and protrudes to the other end of the large intestine.

The scope is bent so the doctor can move it around the curves of your colon. The doctor may occasionally ask you to change positions to help move the range. The endoscope also injects air into the colon, which expands the colon and helps the doctor see more clearly.

You may feel mild cramps during the procedure. You can reduce cramps by breathing very slowly and deeply during the procedure. After the doctor has finished, the colonoscope will slowly be removed while carefully examining the lining of the intestine.

During a colonoscopy test, if the doctor sees an abnormality, a small amount of tissue can be removed for analysis (called a biopsy), and abnormal growths or polyps can be found and removed. In many cases, colonoscopy allows accurate diagnosis and treatment without the need for a major operation.

What happens after the procedure

After the colonoscopy test, it takes about an hour to recover from the sedative. You need someone to drive you home because the full effects of narcotics can take a day to wear off. Don’t drive or make big decisions or return to work for the rest of the day.

If your doctor removes the polyp during your colonoscopy, he or she may recommend that you temporarily eat a special diet.

When you remove the air from your colon, you may feel bloated or pass gas for a few hours after the test. Walking helps eliminate any discomfort.

You may also notice a small amount of blood with your first bowel movement after the test. In general, it does not cause alarm. See your doctor if you continue to have blood or blood clots, or if you have persistent abdominal pain or fever. Although unlikely, it can occur immediately or in the first few days after the procedure, but it can take a week or two.


Your doctor will review the results of the colonoscopy test and share them with you.

Negative result

Colonoscopy test is considered negative if the doctor does not see abnormalities in the colon. Your doctor may recommend that you have another colonoscopy:

  • In 10 years, if you are at risk of colon cancer, you have no risk of colon cancer except age.
  • In five years, if you have a history of polyps in previous colonoscopy procedures

Within a year, if there is residual stool in the colon, it will prevent a full examination of your colon.

Positive result

Colonoscopy test is considered positive if the doctor finds polyps or abnormal tissues in the colon. Most polyps are not cancerous, but some are early. Polyps removed during the colonoscopy are sent to a laboratory for analysis to determine whether they are cancerous, precancerous, or non-cancerous. Depending on the size and number of polyps, you may need to follow a more rigorous surveillance schedule in the future to look for more polyps.

If your doctor finds one or two polyps less than 0.4 inches (1 centimetre) in diameter, he or she may recommend a repeat colonoscopy in five to 10 years, depending on your other risk factors for colon cancer. Your doctor will recommend another colonoscopy sooner if you have:

More than two polyps

  • A large polyp — larger than 0.4 inches (1 centimetre)
  • Polyps and also residual stool in the colon that prevents complete examination of the colon
  • Polyps with certain cell characteristics that indicate a higher risk of future cancer

Cancerous polyps

If you have a polyp or other abnormal tissue that couldn’t be removed during the colonoscopy, your doctor may recommend a repeat exam with a gastroenterologist who has special expertise in removing large polyps, or surgery.

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