Irritable Bowel Syndrome/Inflammatory Bowel Disease

Irritable Bowel Syndrome (IBS) affects 10-20% of the adult population and is more common in women.


Diagnosis and management of Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD) in adults over 18 years or under 45 years of age.

Please note pre-referral criteria are applicable in this referral and referrals will be returned if this information is not contained within the referral letter.

Referral Criteria

A faecal calprotectin is required if the patient is aged between 18 and 45 years

Referrals with a negative result should only go on to gastroenterology if a clinical diagnostic doubt remains in the case of IBS.

If the calprotectin indicates the potential of Inflammatory Bowel Disease (IBD) then the referral needs:

  • Full blood count (FBC)
  • C-reactive protein (CRP)
  • Coeliac serology
  • Faecal Calprotectin numerical result
  • Stool for Microscopy Culture and Sensitivities (MCS),and Ova, Cysts and Parasites (OCP) - if loose stool

Out of scope

  • Patients under 18 years or over 45 years of age
  • Unexplained weight loss
  • Rectal bleeding
  • Family history of bowel or ovarian cancer
  • Age over 60 and change of bowel habit lasting over 6 weeks
  • Iron Deficient Anaemia


Signs and Symptoms

Consider IBS when the patient presents with:

  • Abdominal pain
  • Bloating
  • Change of bowel habit

Then look for positive diagnostic criteria adapted from Rome III

  • Abdominal pain/ discomfort relieved by defaecation or associated with change in stool frequency of form and at least two of the following:
    • Altered stool passage
    • Abdominal bloating
    • Symptoms made worse by eating
    • Passage of mucus

History and Examination

Based on the history, IBS can be divided into:

IBS-D = diarrhoea predominant

IBS-C = constipation predominant

IBS-mixed = alternating

Differential Diagnoses

Differential diagnoses may include:

  • Inflammatory Bowel Disease (IBD)
  • Coeliac disease
  • Pancreatitis
  • Malignancy
  • Infection

​Red Flags

Patients presenting with 'red flag' symptoms need to be investigated/ referred to secondary care through the 2 week wait pathway


In adults 18-45 years old, with symptoms suggestive of IBS and no red flag symptoms nor significant family history:

  • Full Blood Count (FBC)
  • Coeliac serology
  • C-reactive Protein (CRP)
  • Stool for MCS and Ova, Cysts and Parasites (OCP) - if loose stool
  • Faecal calprotectin - Consider the test on patients with new lower gastrointestinal symptoms in order to differentiate between IBS and IBD
  • Sampling from the first bowel movement of the day when the patient is most symptomatic is recommended and may increase the diagnostic yield for proctitis

If all blood tests and faecal calprotectin are less than 45 micrograms/g – reassure and manage as IBS – unless there remains a clinical doubt as to the diagnosis
Negative predictive value 98%; positive predictive of 28%

Where faecal calprotectin is in the range 46-100 micrograms, exclude:

  • Non-steroidal anti-inflammatory drugs (NSAID) ingestion within the last 6 weeks
  • Alcohol ingestion more than 10 units per week for the past 6 weeks
  • Infection
  • Neoplasia
  • Menstruation

This result is equivocal and should be repeated. If the result still remains above 46 micrograms/g, then refer on to gastroenterology

Where faecal calprotectin is 101- 250 micrograms/g - refer to gastroenterology

Where faecal calprotectin is more than 250 micrograms/g refer to gastroenterology urgently

It may also be raised with:

  • Symptomatic diverticular disease
  • Proton Pump Inhibitors (PPIs)

Consider Ca125 +/- ovarian USS in women presenting with new IBS aged over 50. Do not do USS/ bowel imaging/ TSH/ stool culture or H pylori testing unless appropriate to rule out another condition – no test will 'rule-in' IBS.


Conservative options:
  • Lifestyle – create and use relaxation time
  • Physical activity – to increase levels where appropriate
  • Diet and nutrition – regular meals; at least 8 cups of non-caffeinated drinks a day; tea and coffee 3 a day; reduce alcohol and fizzy drinks; limit high-fibre foods such as bran; limit fruit to 3 portions; reduce resistant starch (in processed and re-cooked foods); if diarrhoea reduce sorbitol; if bloating add oats and linseeds; probiotics should be tried for 4 weeks if chosen
Long-term Condition Self-Management Programme

GPs and patients can refer to Improving Lives Plymouth for patient support with any long-term physical or low level mental health condition. The service helps people to better manage their condition and to achieve a better quality of life.

Pharmacological Therapy:
  • Antispasmodic therapy alongside conservative options
  • Laxatives in IBS-C (see 1.6 Laxatives)
  • Loperamide is first choice antimotility agent in IBS-D
  • Adjust both treatments for IBS-C and IBS-D according to stool consistency
  • Consider tricyclic antidepressants (TCA) as second line to laxatives and antispasmodics (see 4.3 Antidepressant drugs)
  • Consider selective serotonin reuptake inhibitors (SSRI) if TCA ineffective (see 4.3 Antidepressant drugs)
Psychological interventions:
  • If no benefit from above after 12 months then consider cognitive behavioural therapy (CBT) - which may be available locally or hypnotherapy on a private basis


Referral Criteria

IBS is a condition to be managed in Primary Care

Referrals should only go on to gastroenterology with a negative faecal calprotectin if there remains a clinical diagnostic doubt in the case of IBS.

If the calprotectin indicates the potential of IBD then refer with:

  • FBC
  • CRP
  • Coeliac serology
  • Faecal Calprotectin numerical value
  • Stool for MCS,and OCP if loose stool

Referrals without this information will be returned.

Referral Instructions

Refer using e-Referral Service:

  • Specialty: GI and Liver (Medicine and Surgery)
  • Clinic Type: Lower GI (medical) excl IBD
  • Service: DRSS-Western-GI and Liver (Medicine and Surgery)-Devon CCG-15N

Refer to Long Term Conditions Self-Management Programme

Referral Forms

DRSS referral proforma

Supporting Information

Patient Information

The IBS Network

Improving Lives Plymouth


NICE guideline CG61 Feb 2015

NICE DG11 2013

Pathway Group

This pathway was signed off by the Western Locality on behalf of the NEW Devon CCG Clinical Pathway Group.

Publication date: 24 June 2016
Updated: October 2018


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