Faecal Calprotectin Testing at ELHT:  Guidance for the use in Adults in Primary Care

The Faecal Calprotectin (FCP) test

Faecal calprotectin (FCP) is a biochemical test that allows the detection of intestinal inflammation through stool analysis. Inflammation increases activity of immune cells e.g. neutrophil granulocytes which release calprotectin. FCP is elevated in inflammatory bowel diseases (IBD) e.g. Crohn’s disease and ulcerative colitis and to a lesser extent in other conditions e.g. neoplasia and polyps.

The test has been recommended by National Institute of Clinical Excellence (NICE) as an option to support clinicians to distinguish between functional disorders (such as Irritable Bowel Syndrome – IBS) and Inflammatory Bowel Disease (IBD).

Why is the FCP test useful?

GP’s are happy managing most clear cases of IBS in primary care. Other patients are clearly more symptomatic with unacceptable frequency of defecation, blood in their stools or raised inflammatory markers. These patients clearly need a referral to gastroenterology, as they probably have a diagnosis of IBD.

There is a grey area in the middle though. Some patients have a lot of symptomology from IBS, but no clear features of IBD. Other patients are very anxious about their symptoms and want referral for reassurance. In these patients, a negative FCP test will reassure, avoiding unnecessary referral to secondary care and the need for further invasive investigation.

Although sigmoidoscopy or colonoscopy with biopsy is considered the ‘gold standard’ procedure for assessing intestinal inflammation it is invasive carrying a risk of complications and is uncomfortable for the patient. By prioritising the most appropriate patients for referral  FCP testing may reduce the time required to make a diagnosis of IBD.

There is robust evidence to support the use of FCP as a marker for intestinal inflammation.  FCP has been demonstrated to be sensitive and specific enough to be utilised for this purpose.

FCP testing has a high negative predictive value in the correct context and therefore allows clinicians to rule out intestinal inflammation with a degree of confidence.

However, if a clinician strongly suspects IBD on clinical grounds, FCP is not useful and a direct referral to secondary care is more appropriate.

Sample requirements

Around 1g sample of faeces should be collected into a plain FECON container. Collect samples Monday- Thursday only to arrive in the laboratory on the day of collection. Do not freeze samples

Guidance for the use of FCP in Primary Care


Clinical scenarios where FCP may be useful:

Chronic diarrhoea with abdominal pain or discomfort that is relieved by defecation, or passage of mucus and bloating, where the clinician suspects IBS, but has a level of suspicion that there may be a diagnosis of IBD.

In patients who are very anxious about their symptoms, and want further investigation, and a negative test will reassure, and enable the GP to make the most appropriate decision regarding a referral.

                Clinical scenarios where FCP is NOT appropriate:

Patients with a clear diagnosis of IBS where IBD is not suspected.

Suspected cancer – if cancer suspected use separate 2WR referral mechanism

Unexplained anaemia, weight loss or rectal bleeding  – direct referral to secondary care is required

New onset GI symptoms in patients aged >50 yrs.

Avoid testing if there is known infectious diarrhoea, NSAID use, or current menstrual bleeding

FCP is an expensive test, and should be used within the limits of this guidance


     Arrange first line investigations 


Coeliac screen

Faecal calprotectin


Greater than 50ug/g

Refer to gastroenterologist for further assessment (intestinal inflammation




Less than 50ug/g

Intestinal inflammation unlikely

Secondary care investigation not usually necessary

Management in Primary Care appropriate including reassurance, information  leaflets and symptomatic control with medication



Alternative causes of a raised FCP include:

  • Gastro-intestinal infection/bleeding
  • Colorectal neoplasia
  • Polyps
  • Non-steroidal anti-inflammatorydrug induced enteropathy 

Please also see: https://www.nice.org.uk/Guidance/DG11

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