GI Investigations · Patient Guide
A Change in Bowel Habit: Which Tests Are Actually Indicated?
Everyone's bowels vary. A persistent change from your normal is different — and has a well-defined investigation pathway.
Bowel habit varies with diet, stress, travel and medication, and short-lived change rarely means anything. A persistent change — looser or harder, more or less frequent, lasting more than three to four weeks without explanation — is one of the classic symptoms medicine takes seriously, because it's a recognised early flag for treatable bowel disease.
What the work-up looks like
Assessment starts with history and examination, then first-line tests: blood tests (including thyroid and coeliac screening), FIT, and often faecal calprotectin in younger patients. These triage tests decide how quickly the definitive question — direct examination of the bowel by colonoscopy — needs answering. In older patients or with alarm features, colonoscopy is indicated regardless of what the preliminary tests show.
When this test is usually indicated
- Blood tests, FIT and calprotectin: the universal first step for a persistent change
- Colonoscopy: any persistent change from age 50 onwards, or from 40 with additional features
- Colonoscopy: change accompanied by bleeding, anaemia, weight loss or family history
- Colonoscopy: a positive FIT or raised calprotectin at any age
- Earlier assessment when narrowing stools or a sensation of incomplete emptying appear
When it may not be the right test
- Colonoscopy for a change explained by a new medication, once withdrawal resolves it
- Imaging (ultrasound or routine CT) as the primary test — the bowel lining needs direct examination
- Attributing a new persistent change to long-standing IBS without reassessment — IBS doesn't newly change in later life
- Waiting for the next screening invitation instead of investigating an active symptom
The trap with bowel-habit change is normalisation — 'probably my diet' for months on end. The evidence is unambiguous that earlier-investigated disease is dramatically more treatable, and the majority of investigations end in reassurance. Both facts argue the same way: get it looked at.
What happens if you do need it
A private consultation compresses the pathway: examination and bloods at the first visit, stool tests immediately, and colonoscopy within days where indicated — performed by Mr Papettas as a JAG dual-accredited endoscopist. Most patients leave the process with a benign explanation and a plan; the minority with significant findings gain the thing that matters most, which is time.
Frequently asked questions
How long is a 'persistent' change?
More than three to four weeks without an obvious explanation is the conventional threshold for taking it seriously.
Can medication change bowel habit?
Very commonly — metformin, iron, opioids, antacids and antibiotics are frequent culprits. A medication review is part of the assessment, not a reason to skip it.
Is constipation as significant as diarrhoea?
A persistent change in either direction counts; a genuine change from your own normal is what matters.
Could it just be IBS?
Possibly — but IBS is a diagnosis made positively in the right context, not a label for an uninvestigated new change, particularly past 40.
What blood tests are involved?
Full blood count, ferritin, inflammatory markers, thyroid function and coeliac screening — each excludes a specific mimic.
How quickly can I be assessed privately?
Consultation within days at Nuffield Health Warwickshire — call 01926 935121.
Related reading
Unsure whether you need this test?
Mr Trif Papettas FRCS is a Consultant Colorectal and General Surgeon at Nuffield Health Warwickshire Hospital, Leamington Spa, and a JAG dual-accredited endoscopist. A consultation settles which investigation, if any, your symptoms actually need — and if a test is indicated, it can usually be arranged within days.
Self-referrals welcome · No GP letter required · Self-pay and insured patients seen at Nuffield Health Warwickshire Hospital, Leamington Spa CV32 6RW