Evaluation of guidelines for the use of faecal calprotectin testing in primary care

The Department of Gastroenterology at York Teaching Hospital NHS FT and Vale of York CCG developed evidence-based guidelines to support the pragmatic use of FC in primary care. The guidelines incorporated: a higher FC cut off value of 100mcg/g rather than the standard normal range of 50mcg/g, a ‘traffic light’ system for risk assessment, a test repeat when of intermediate risk and a clinical management pathway. The guidelines were designed to maintain the high NPV of FC whilst improving the previously poor PPV. It was hypothesized that this would: 1 identify patients highly likely to have functional disease and provide a structured pathway for their treatment and evaluation; 2 identify those patients at risk of organic disease for referral into secondary care without overwhelming that service with false positives. The guidelines were evaluated by means of an audit.

NICE (Diagnostic Guidance 11) have recently recommended FC testing as an option in adults with lower gastrointestinal symptoms for whom specialist investigations are being considered, if cancer is not suspected and it is used to support a diagnosis of IBD or IBS. Currently there is very little direct evidence from primary care to support the implementation of this guidance. The low incidence of IBD in primary care and the poor PPV of FC means that FC testing may not enhance diagnostic evaluation but instead may overwhelm secondary care services because of the inappropriate referral of false positive patients. An evaluation of a structured guideline for the use of FC in primary care was seen as a possible solution.

The audit of guidelines was registered by the Clinical Effectiveness and Improvement Unit at York Hospital, no: 3232. The audit was supported by NICE HTAP.  Lead-in time was 3 months.

Five primary care practices were invited to enter the evaluation. Educational presentations were given to each practice, a site lead identified and the data sets were agreed. On going support was offered.

Patients with new lower gastrointestinal symptoms, aged 18-60years, were entered into the guidelines where:

• cancer was not suspected
• the likely diagnosis was IBS or IBD but where there was clinical uncertainty in that diagnosis
• there were normal or negative initial investigations as judged appropriate by the GP

Guidelines directed as follows:

Patients with a low FC (<100mcg/g) were treated on the presumption that IBS was likely with positive reassurance, local guidance and review at six weeks with routine referral to the Department of Gastroenterology at York Hospital at that point if they were still symptomatic.

In patients with an intermediate FC result (100-250mcg/g) the test was repeated two weeks later and action thereafter was as directed by that result. Non steroidal anti-inflammatory drugs (NSAID) and aspirin were asked to be avoided if clinically safe or reasonable to do so. A repeat result <100mcg/g prompted expectant, positive, local management as outlined above; a repeat of 100-250mcg/g prompted routine referral to the Department of Gastroenterology at York Hospital. Here the Gastroenterologist would investigate and manage as judged clinically appropriate.

A high risk FC result of >250mcg/g directed to a ‘straight to test’ urgent colonoscopy at York Hospital or an urgent outpatient review if the patient was of a poor performance status.

Patients were entered into the audit for six months from March to August 2014. Clinical outcomes were followed for a further six months during which an evaluation was made.

Comparator secondary care referral data from a neighbouring Trust was obtained.

A GP survey of the guideline was undertaken

Two hundred and sixty two patients were evaluated. 67% were female and the mean age was 38y. Presenting symptoms were diarrhoea 43%, alternating bowel habit 11%, constipation 6%, bleeding 6%, abdominal pain 22%, bloat 4%, none given 6%. 67% of patients with FC<100 were successfully  managed locally. 33% were subsequentlyreferred and 15%  had colonic or cross-sectional investigations.

The guidelines for use of FC  in primary care had a NPV of 97% for IBS ( and non-intestinal disease) and a PPV of 40% for  IBD or other organic intestinal disease.

False negatives were: 

• coeliac disease (2 patients)
• diverticulosis (2 patients)
• microscopic colitis (1 patient)
• pancreatic failure (1 patient)
• 30mm low grade tubulovillous adenoma (1 patient)

This compares with 98% and PPV of 21% using the standard FC cut off of >50mcg/g alone.

The guideline outcomes were better than GP clinical judgment alone and delivered a higher diagnostic yield after secondary care referral (21%) than the conventional (that is current) comparator pathway (5%).

89% of patients with IBD (ulcerative colitis; 4 patients and Crohn’s disease 5) had a FC >250mcg/g and patients were diagnosed by ‘straight to test’ colonoscopy on average within three weeks of referral. The C-reactive protein was normal in 67% of patients with IBD.

The guidelines were considered helpful by GPs who made a number of observations:

“It has been really useful to have a clear set of guidelines for investigating and managing patients with symptoms which would suggest IBS being the most likely diagnosis.”

“I found it a very useful part of feeling confident to exclude borderline cases where uncertain if could be inflammatory bowel disease or irritable bowel disease.” “It also helps a great deal when reassuring and educating patients who are otherwise opposed to a diagnosis of IBS.”

“If this is rolled out across the CCG/ nationally, then education would need to be provided to ensure the test is used appropriately and the results understood.”

Conclusion: This audit outlines the potential role for FC in primary care diagnostics. It incorporates risk assessment to support clinical judgement, a cut off of 100, repeat testing if >100 & straight to test for high-risk investigation. A revised guideline has been developed that we propose to implement at scale across Yorkshire and Humber. Key to its success are:

• early identification of stakeholders,
• communication of the pathway and
• educational support