Introduction Irritable bowel syndrome (IBS) has a prevalence of around 15% in the UK and up to 20% are referred to secondary care. Current practice shows that GPs are excellent at identifying and referring cases of inflammatory bowel disease (IBD) but due to the high prevalence of IBS, 60% of outpatient colonoscopies performed are normal. Faecal Calprotectin (FCP) is recommended by NICE to assist differentiating IBD from IBS in patients where cancer isn’t suspected. This was expected to speed the time to diagnosis, reduce referrals and unnecessary endoscopies. Implementation across the UK is patchy. Locally the test was instituted for primary care without the development of an agreed care pathway as recommended by NICE.
Methods A retrospective audit of 193 consecutive patients with primary care initiated FCP tests from 01/02/15-02/02/15 were reviewed. Referral information, demographics, blood results, endoscopy and histology reports as well as patient outcomes were extracted from hospital and primary care IT systems using a standardised proforma. 10 paediatric cases were excluded. We aimed to assess the outcomes of testing in the absence of agreed clinical guidelines.
Results Complete data was available for 183 adult patients. 29.5% did not meet NICE criteria for FCP testing. 20% met criteria for suspected colorectal cancer referral. 91.2% of patients with negative results (FCP < 50 mcg/g) were managed in primary care and only 54% of patients with a positive result (>100) were referred for further investigation. 28.6% of patients with indeterminate results (50–100) had a repeat test, of which 70% were persistently abnormal but only 20% were subsequently referred. No patients were assessed for factors which may cause false positive results. 82% of endoscopies were performed in patients with a positive FCP. 14% of the patients scoped were diagnosed with IBD, all had a positive FCP but only 37% had abnormal blood tests.
Conclusion Use of FCP testing in the absence of a clear pathway leads to poor compliance with NICE guidance and is inappropriate in nearly 1/3rd of patients. There is clear reliance on the negative predictive value to avoid referral but this approach does not account for the highly variable pre-test probability and consequent detrimental effect on reliability. FCP is used too often in patients with unclear indications: upper GI symptoms; short symptom duration or suspected cancer criteria. False positive confounders do not appear to be considered, resulting in inconsistent retesting of indeterminate results. The results suggest that without a clear pathway FCP is commonly misused and misinterpreted, with the potential to delay or even fail to diagnose major GI pathology. This supports the use of a clear pathway for testing which we have now developed.
Disclosure of Interest None Declared