Diagnosing Ulcerative Colitis

Diagnosing Colitis

On the Colitis forums I've seen a few people, yet to be diagnosed, asking about the different procedures they'd been told about or have an appointment for - hopefully the simple explanations below will help.

Diagnosing Ulcerative Colitis

If symptoms of Colitis are mild it can take a long time to be diagnosed - this is probably because symptoms often come and go and also because they can appear to crossover with many other ailments e.g. IBS.

I've read about UCers who suspect they had Colitis for 10 years and longer before they were diagnosed. This is because the symptoms they'd experienced during different periods weren't conclusive e.g. diarrhea, cramps, aches, feeling rundown. Generally it's only after a colonoscopy that a Doctor can diagnose Ulcerative Colitis with any degree of certainty.

Because my symptoms were mild, I had a period of over a year before I was diagnosed, which is quite common. Up until then, the Doctors and Specialists didn't know what was causing the problem (in my case, blood in the stool). Initially I had blood tests, then I had two separate Rigid Sigmoidoscopy (with months in between), and finally a Colonoscopy.

It goes without saying that if symptoms are more severe, there's more urgency to diagnose the problem and begin a regime of meds to improve the situation. This doesn't necessarily mean a definitive diagnosis will be quick though. Again, the problem being that symptoms of Colitis can crossover with many diseases. However, where symptoms are more severe, a Colonoscopy would be arranged at an earlier date which should at least lead to a diagnosis of 'Colitis'.

Path of Diagnosis

Initial tests:

Arranged when a local Doctor decides explanations by their patient give clear signs that symptoms could be linked to Colitis.

Where symptoms are mild, the initial stage of tests can involve taking stool, blood samples and a biopsy in order to find signs of infection, vitamin / mineral deficiency and inflammation.

However, even if there are clues that suggest Colitis, a sigmoidoscopy or colonoscopy will still be required for a definitive diagnosis.

Generally there is a period of time before the UCer can meet a GI Specialist to discuss the results and the next steps to take - during this waiting time meds may be prescribed (Mesalazine, Pentasa etc.) with the hope that when the UCer finally meets with the GI, the symptoms have diminished.

Often meds are NOT prescribed before meeting the specialist - I wasn't prescribed any meds during the time GI Specialists were trying to diagnose my symptoms, although my symptoms were mild.


Enables the specialist to view the rectum and the sigmoid colon. There are two types:

  • Flexible Sigmoidoscopy: the procedure takes around 20 minutes and can enable the specialist to view up to 60 to 70cm along the colon, part way into the descending colon. Preparation before the procedure is an enema the night before and an enema in the morning.
  • Rigid Sigmoidoscopy: used less these days, it enables the specialist to view around 20 to 25cm along the colon and is generally used when the problem area is thought to be based in the rectal region. Preparation is suppository or enema.

when it's used:

This test can take place where initial tests aren't conclusive. It can also take place if the sufferer gives clues that symptoms seem to be localised near the exit or when symptoms are slightly more severe on an initial visit to the Specialist.

A diagnosis of Proctitis and/or Proctosigmoiditis is possible from a Sigmoidoscopy, but a Colonoscopy may still be required if the results of the Sigmoidoscopy aren't conclusive.

Colon Sigmoidoscopy for Colitis


Enables the specialist to view the entire large colon by moving a flexible tube with a tiny camera through it. Gives the most accurate results in relation to extensive Ulcerative Colitis.

The procedure takes around 20 to 30 minutes and the patient is usually sedated (drowsy but not asleep). However, I've read about some UCers not having sedation because they weren't offered it or had refused it for various reasons e.g. because they wanted to drive home after the procedure.

Unless there's a medical reason why you can't have sedation, it's your right to have it! If you want sedation but aren't offered it - ask for it!

Preparation is with liquid laxatives in the form of drinks; these clear the entire colon. Generally taken a specific number of hours before the procedure (often the night before and again in the morning).

when it's used:

This test can take place when the previous tests weren't conclusive. It can also take place if the sufferer gives clues that symptoms seem to be further along the colon e.g. pains higher up the diaphragm or when symptoms are more severe on an initial visit to the Specialist.

After the Colonoscopy a diagnosis of Ulcerative Colitis affecting any part of the large colon should be possible. Unfortunately for some, this can change after time when it becomes apparent that the sufferer actually has Crohn's - something a Colonoscopy won't necessarily discover.

Although a Colonoscopy is the most accurate way of detecting Ulcerative Colitis, other techniques used can be Xray or MRI scan. I've read about UCers having this done where inflammation meant a Colonoscopy was not possible.

Colonoscopy for Colitis