The term “colonoscopy” means looking inside the colon. This is a procedure used to view large intestine (colon and rectum) using an instrument called colonoscope (a flexible tube with a small camera and lens attached). The procedure can detect inflamed tissue, ulcers, and abnormal growths. It is used to diagnose early signs of colorectal cancer, bowel disorders, abdominal pain, muscle spasms, inflamed tissue, ulcers, anal bleeding, and non-dietary weight loss. It is also used to collect tissue samples (biopsy).
Colon examination is recommended when symptoms like blood in stools, unexplained abdominal pain and change in bowel habits are seen. This procedure can be used to detect bowel diseases like Crohn’s Disease or Ulcerative colitis. It is a procedure performed by a gastroenterologist, a well-trained subspecialist.
In London, at Kensington International Clinic, our consultants carry out private colonoscopy on a daily basis, in a setting designed for comfort, privacy and rapid access.
Why its' done ?
INVESTIGATE INTESTINAL SIGNS AND SYMPTOMS
A colonoscopy can help your doctor explore possible causes of abdominal pain, rectal bleeding, chronic diarrhea and other intestinal problems.
SCREEN FOR COLON CANCER
If you’re age 45 or older and at average risk of colon cancer, you have no colon cancer risk factors other than age, your doctor may recommend a colonoscopy every 5 years. If you have other risk factors, your doctor may recommend a screen sooner. This procedure is one of a few options for colon cancer screening. Talk with your doctor about the best options for you.
LOOK FOR MORE POLYPS
If you have had polyps before, your doctor may recommend a follow-up colonic endoscopy to look for and remove any additional polyps. This is done to reduce your risk of colon cancer.
TREAT AN ISSUE
Sometimes, a colonoscopy may be done for treatment purposes, such as placing a stent or removing an object in your colon.
Full overview of the procedure
Below is a step-by-step overview of what to expect when you book a colonoscopy in London at our clinic, from preparation through to your results.
1 - PRE-PROCEDURAL PREPARATION
Before a colonoscopy, you’ll need to clean out (empty) your colon. Any residue in your colon may make it difficult to get a good view of your colon and rectum during the exam.
To empty your colon, your doctor may ask you to:
- Follow a special diet the day before the exam : typically, you won’t be able to eat solid food the day before the exam. Drinks may be limited to clear liquids, plain water, tea and coffee without milk or cream, broth, and carbonated beverages. Avoid red liquids, which can be mistaken for blood during the test. You may not be able to eat or drink anything after midnight the night before the exam.
- Take a laxative : your doctor will usually recommend taking a prescription laxative, usually in a large volume in either pill form or liquid form. In most instances, you will be instructed to take the laxative the night before or you may be asked to use the laxative both the night before and the morning of the procedure.
- Adjust your medications: remind your doctor of your medications at least a week before the exam : especially if you have diabetes, high blood pressure or heart problems or if you take medications or supplements that contain iron. Also tell your doctor if you take aspirin or other medications that thin the blood, such as warfarin (Coumadin, Jantoven); newer anticoagulants, such as dabigatran (Pradaxa) or rivaroxaban (Xarelto), used to reduce risk of blot clots or stroke; or heart medications that affect platelets, such as clopidogrel (Plavix).
You may need to adjust your dosages or stop taking the medications temporarily.
2 - DURING THE PROCEDURE
Procedure
A Colonoscopy takes between 15 and 30 minutes. During this examination, the doctor inserts a thin, flexible tube, about the size of a finger, into your rectum. This tube, called a ‘colonoscope’, ends in a tiny camera. This camera allows you to see the inside of the large intestine and transmit the images to a screen.
Because the inside of the bowel is easier to see when it is swollen, the doctor will use a device to push air into it. This swelling may be uncomfortable or painful. For this reason, the doctor may offer you a medicine (painkiller) to reduce the discomfort or pain. The doctor may also give you a relaxing medication (sedative) to help you relax during the examination.
In addition to examining the inside of the large intestine, the doctor may also sometimes perform other procedures during the examination:
- Remove polyps.
- Taking a biopsy.
Removal of polyps
A Colonoscopy can sometimes show that there are polyps in the bowel. Polyps are small wart-like masses of flesh that grow on the inner walls of the large intestine. As some polyps can develop into colorectal cancer, doctors usually prefer to remove them as a preventive measure.
Biopsy
If deemed necessary, the doctor may also decide to perform a biopsy. A biopsy is the removal of a piece of tissue from the walls of the large intestine.
Polyp removal and biopsy are painless procedures. The polyps or tissue collected is then analysed in a laboratory to see if it is cancerous or if there is another disease. The results of the analysis will be sent to your doctor, who will follow up with you as appropriate.
3 - POST-OPERATIVE CARE
After the examination, it takes about an hour to start recovering from the sedative. You will need someone to drive you home, as the effects of the sedative can take up to a day to wear off completely. Do not drive, make important decisions or return to work for the rest of the day.
You may feel bloated or have gas for a few hours after the examination while you clear the air from your colon. Walking may help to relieve the discomfort.
You may also notice a small amount of blood in your first bowel movement after the examination. This is not usually a cause for concern. Consult your doctor if you continue to pass blood or blood clots, if you have persistent abdominal pain or if you have a fever. Although unlikely, this may occur immediately or in the first few days after the procedure, but may be delayed by one to two weeks.
4 - YOUR RESULTS
Your doctor will review the results and let you know.
Negative result
A colonoscopy is considered negative if the doctor finds no abnormalities in the colon.
Your doctor may recommend that you have another colonoscopy:
- In 10 years, if you are at average risk of colon cancer and have no risk factors for colon cancer other than age, or if you have small, benign polyps.
- In 1 to 7 years, depending on a number of factors: the number, size and type of polyps removed; whether you have a history of polyps in previous colonoscopies; whether you have certain genetic syndromes; or whether you have a family history of colon cancer.
If residual stool in the colon has prevented a full examination of your colon, your doctor may recommend a repeat colonoscopy. The time frame will depend on the amount of stool and the part of the colon that could be examined. Your doctor may recommend a different bowel preparation to ensure that your bowels are completely emptied before the next investigation.
Positive result
A colonoscopy is considered positive if the doctor finds polyps or abnormal tissue in the colon.
Most polyps are not cancerous, but some may be pre-cancerous. The 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 undergo a more rigorous surveillance programme in the future to look for more polyps.
Problems with the examination
If your doctor is concerned about the quality of the view through the endoscope, they may suggest repeating the colonoscopy or shortening the interval before the next examination. In cases where the endoscope could not be advanced through the entire colon, a virtual colonoscopy might be recommended to assess the remaining sections.
Colonoscopy: weighing the pros and cons
ADVANTAGES
- Colonoscopy is more precise than an X-ray. This procedure also allows other instruments to be passed through the colonoscope like removal of a suspicious-looking growth or to take a biopsy-a small piece for further analysis. In this way, colonoscopy may help to avoid surgery or to better define what type of surgery may need to be done.
- It’s a safe and effective way to evaluate problems such as blood loss, pain, and changes in bowel habits such as chronic diarrhoea or abnormalities that may have first been detected by other tests. This exam can also identify and treat active bleeding from the bowel.
- The procedure is also an important way to check for colon cancer and to treat colon polyps, abnormal growths on the inside lining of the intestine. However, it is not possible to tell just by looking at a polyp if it is malignant or potentially malignant. This is why colonoscopy is often used to remove polyps, a technique called a polypectomy.
RISKS & COMPLICATIONS
As with any procedure, colonoscopy involves certain risks and potential complications. You may experience pain and discomfort but risks and complications associated with this kind of exam are rare and minor. These include a reaction to the sedatives, bleeding at the site of biopsy or very rarely a tear in the colonic wall.
You should consult your doctor immediately if you experience fever, rectal bleeding or severe abdominal pain after a colonoscopy.
For further questions about private colonoscopy preparation, sedation, results or pricing in the UK, see our FAQ below.
Meet our doctors at our London colonoscopy clinic
Booking info: a £70 prepayment is required at the time of booking. The balance is settled on the day of your consultation.
Cancellation policy: full refund if cancelled more than 72 hours in advance; the £70 prepayment is retained between 48 and 72 hours; full consultation fee charged under 48 hours.
Health insurance: Kensington International Clinic is recognised by several British and international private insurers. Many health insurance schemes, particularly for expatriates, cover all or part of a dermatology consultation when medically indicated. We recommend checking your cover directly with your insurer before your appointment, and sharing your policy number with us if direct billing is needed.
FAQ
What are the reasons for an urgent colonoscopy ?
Most colonoscopies are scheduled procedures, but some clinical situations call for urgent investigation. An urgent colonoscopy is typically recommended in the following cases:
- Persistent or heavy rectal bleeding;
- Unexplained iron-deficiency anaemia with signs of occult digestive bleeding;
- Sudden and significant change in bowel habits, especially with weight loss;
- Suspected bowel obstruction or a mass identified on imaging (CT scan, MRI);
- New or worsening symptoms in patients with a strong family history of colorectal cancer;
- Severe abdominal pain associated with red flags (fever, vomiting, rectal bleeding).
If you present with any of these signs, contact your doctor without delay so that the right level of urgency can be assessed.
What happens if cancer is found during a colonoscopy?
If a suspicious lesion is identified during your colonoscopy, your gastroenterologist will not provide a definitive diagnosis on the day.
The standard pathway involves several steps:
- A biopsy is taken from the lesion for laboratory analysis;
- The site may be marked with a small medical-grade ink tattoo to help any future surgeon locate it;
- Pathology results are usually available within 1 to 2 weeks;
- If cancer is confirmed, your case is reviewed by a multidisciplinary team (MDT) bringing together gastroenterologists, surgeons, oncologists and radiologists;
- A personalised treatment plan is then proposed, which may include surgery, chemotherapy, radiotherapy or a combination, depending on the stage and location.
Early detection through colonoscopy significantly improves outcomes, which is why timely investigation matters.
How long does a colonoscopy take?
The procedure itself is short, but you should plan for a longer visit overall.
Here is what to expect on the day:
- Pre-procedure check-in, change and IV access: 30 to 45 minutes;
- The colonoscopy itself: 15 to 30 minutes on average;
- Recovery from sedation in our dedicated recovery area: around 1 hour;
- Total time at the clinic: 2 to 3 hours from arrival to discharge;
- Return home: a responsible adult must collect you, as you cannot drive for the rest of the day.
You should plan to take the day off work and avoid important decisions until the sedation has fully worn off, usually within 24 hours.
What sedation is used for colonoscopy in the UK?
Three sedation options are commonly offered for colonoscopy in the UK, and the choice is discussed with you before the procedure:
- No sedation: chosen by some patients who prefer to drive home immediately, but tolerance varies and many find this uncomfortable;
- Conscious sedation with midazolam (a benzodiazepine) combined with fentanyl (an analgesic): the most common option in UK practice, allowing you to remain responsive while feeling relaxed and largely pain-free;
- Entonox (gas and air): a lighter alternative used in some centres, taken on demand during the procedure;
- General anaesthesia: reserved for specific cases (severe anxiety, complex procedures), administered by a consultant anaesthetist.
At Kensington International Clinic, your gastroenterologist will discuss the most appropriate sedation option with you during your initial consultation, taking into account your medical history, anxiety level and personal preferences.
