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Medical editor Arild Nesbakken MD
Professor of Surgery
Oslo University Hospital


Colonoscopy is performed when:

  • proven blood (visible or occult), or other symptoms suggestive of colorectal cancer.
  • screening of asymptomatic patients with known hereditary risk of colorectal cancer.
  • postoperative control after colon cancer surgery.
  • control in inflammatory bowel disease (IBD).


  • Uncover polyps or infiltrating cancer of the colon and rectum.
  • Postoperative control of the anastomosis areas concidering recurrence of cancer or stricture formation.
  • Postoperative control to check whether new polyps or cancer (metachronous) has occurred.
  • Assessing disease activity and any development of dysplasia by IBD.


  • Coloscope with associated equipment
  • Biopsy forceps
  • Sling for removal of polyps


  • Fasting is not necessary. High-fiber bread, cereals, linseed or fruits/vegetables with a lot of seeds should be avoided the last five days before the examination.
  • Patients should avoid iron supplements in the last seven days before the examintaion.
  • Bowel emptying through taking oral laxative solutions (an abundant bowel emptying is necessary).
  • If the patient uses anticoagulants and it is necessary to take biopsies or slinging polyps (usually), the patients should consult their doctor to ensure the safety of taking a break in the medication according to the following rules:
    • Plavix® and equivalent antiplatelet is not to be discontinued if they have been in use < 1 year, otherwise stop may be considered.
    • Pradaxa®, Xarelto® and Eliquis® must be stopped two days before the examination, earlier if renal impairment.
    • Restarted after two days if a sling resection or another examination that can cause bleeding is performed.
    • Marevan® (warfarin) is stopped five days before the examination. INR is measured an hour before the procedure and should be below 1,8. If the patient has a high risk of thrombosis (heart valve and others) low molecular weight heparin must be considered. Start with double dose of Marevan® (warfarin) the same evening.
    • Albyl-E® (Acetylsalicylic Acid) can be continued.

If it is contraindicated to discontinuate (for example dual antiplatelet agent), and there is an indication to perform the examination as soon as possible, a tailored program should be made in collaboration with the general practitioner and possibly a cardiologist/haematologist.

  • Any other medications in the morning can be taken as usual.
  • If the patient has diabetes and use insulin, an appointment early in the day can be made.
  • The bladder should be empty before the examination.


  • Before total colonoscopy premedication with intravenous analgesics and possibly sedation are usually administered.
  • The patient is located in a left lateral position.
  • The anal canal is lubricated and palpated with a finger to ensure that the canal is open.
  • The coloscope is being inserted and it is attempted to use as little air as possible during insertion to minimize discomfort.
  • As the scope is inserted upwards the patient turns into a supine position, possibly another position.
  • If there is difficulties during the insertion the assistant will "stabilize" the intestine by holding his hands on the patient´s stomach.
  • If the patient experiences the examination as painful, more medications are administered.
  • The scope is rapidly, but gently inserted to the cecum, possibly into the terminal ileum. Then more air is filled in and the scope is slowly pulled down while all parts of the intestine are being visualized.
  • Any lesions are being biopsied, or possibly removed.

The examination lasts for about 15 - 60 minutes.


  • The patient can eat and drink immediately after the procedure, unless otherwise indicated.
  • The patient can usually go home quite immediately. If he/she is tired after the examination/medications, or a procedure that leads to increasing risk for complications is performed, the patient may be in the hospital for observation in one to three hours before going home.
  • The patient is informed about possible complications:
    • Bleeding from the rectum if polyps are removed.
    • Abdominal pain which do not disappear quickly after a completed examination, may lead to suspicion of bowel perforation. This may occasionally occur during diagnostic colonoscopy, while it is more common after biopsy/sling resection.

The physician in charge of the examination is following up test results and informs the patient about any further investigation and control.

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