FC can be useful test for IBD in older patients as long as cancer is not suspected
Faecal calprotectin (FC) can still be a useful test for ruling on inflammatory bowel disease in older adults as long as colorectal cancer is not suspected, UK researchers have concluded.
A study comparing use of the test in those under and over 50 years of age found it is sensitive for inflammatory bowel disease (IBD) and other organic GI pathology across the age groups.
But the study following almost 700 patients found that the specificity and positive predictive value of FC was low particularly in adults over 50 years old at a threshold of 50 µg/g, most likely because other pathology such as colonic polyps and diverticular disease, are more common.
FC testing is widely used in primary care as a marker of gastrointestinal inflammation but many guidelines advise against its use in older adults, the researchers noted in the British Journal of General Practice.
Although the study showed FC was useful to aid in diagnosis in older age groups, the team added that it would be ‘essential to accurately stratify patients with “red-flag” symptoms to ensure appropriate referral is made to exclude colorectal cancer’.
The analysis which reviewed data from 669 patients who had undergone FC testing followed by a colonoscopy to see how the test performed showed an FC >50 µg/g provided a high sensitivity for inflammatory bowel disease at 94.1% in those aged 18–49 years and 93.8% in those aged ≥50 years.
It also outperformed FIT testing when it came to the diagnosis of inflammatory bowel disease and other organic GI pathology, they reported.
In all 10% of consultations in primary care are related to gastrointestinal symptoms and establishing effective pathways for their investigation is key, the researchers from Imperial College London said.
The findings highlight the ‘continued role for FC’ in older age groups, if focused on testing patients for whom there is a possibility of IBD but a low likelihood of colorectal cancer, they concluded.
‘The poor performance of symptoms alone in the detection of IBD and organic GI pathology supports non-invasive testing at initial assessment, when immediate referral is not indicated,’ they added.
In practice, the use of FC in older adults by GPs could help in the stratification of patients who have a negative FIT and GI symptoms to exclude significant pathology, they advised.
‘An elevated FC in this group of patients could potentially identify those ‘who would benefit from further investigations’, whereas a negative FC could provide reassurance, they said.
Dr Robert William Perry, study leader and a gastroenterology clinical research fellow, said: ‘If patients present with symptoms that according to the NICE guidelines are potentially suggestive of colorectal cancer then obviously they should be evaluated appropriately with FIT testing or onward referral.’
In younger patients there was clearly a role for FC in differentiating between organic GI diseases and IBD but in older patients its use would be in a much narrower group ‘and shouldn’t be used where cancer is suspected’.
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