Patients with suspected inflammatory bowel disease (IBD) could avoid unnecessary colonoscopy tests and speed up diagnosis by using multiple home testing kits, a new study has found.
Researchers from the University of Birmingham, UK, have developed a unique testing protocol to improve IBD referral triage by combining a new 13-point symptom checker with the results of multiple faecal calprotectin (FCP) tests.
Obtaining a second FCP result prevented patients from undergoing unnecessary colonoscopies. The findings could reduce the need for expensive and intrusive investigations, speed up diagnosis for many IBD patients, and support self-diagnosis to secondary care. This would, in turn, reduce the burden on primary care.
The study, published in the journal Frontline Gastroenterology, is the first in the UK to prospectively examine the symptoms of IBD and levels of faecal calprotectin (FCP) from the onset of the condition.
Patients with IBD, including Crohn’s disease and ulcerative colitis, often have a long wait until diagnosis, and the researchers note that the current testing system is under immense strain. Diagnostic delays for IBD can result in adverse outcomes for patients.
The two-year study, which took place between January 2021 and August 2023, involved 767 participants. Over half of those who took part (n=423, 55%) were diagnosed with IBD: 208 with Crohn’s disease and 215 with ulcerative colitis.
A 13-point symptom history was taken prediagnosis, and clinical indices such as repeat FCP were collected prospectively.
The most common symptoms, which were not always easily distinguished from non-IBD symptoms, were abdominal pain (84%), looser stools (84%) and fatigue (79%) for Crohn’s disease and per-rectal bleeding (94%), urgency of stools (82%), and looser stools (81%) for ulcerative colitis.
The researchers found blood in the stools and weight loss to be the strongest predictors of IBD. The results showed that a person with blood in their stools was over four times more likely than those without to have Crohn’s disease (based on a measurement of an odds ratio (OR) of 4.38 with a 95% confidence interval and a range of 2.40 to 7.98) and over three times more likely to have weight loss (OR 3.39; 2.14–5.38).
Patients diagnosed with ulcerative colitis were 33 times more likely to experience blood in their stools and over two times more likely to have weight loss (OR 33.68; 15.47–73.33 and OR 2.33; 1.37–4.00, respectively).
Serial FCP measurements were found to be more useful than a single test for predicting IBD accurately.
Two FCP measurements, where one is greater than 100 µg/g and the other greater than 200 µg/g, were shown to be associated with the diagnosis of IBD. However, a second result, ≥220 µg/g, when considered alone and regardless of the first result, was more accurate at predicting IBD.
Some patients with elevated FCP levels and were suspected of having IBD were re-tested and showed a reduction in levels since the first measurement, indicating the initial elevated levels of FCP were not due to IBD.
Using the findings, the researchers have developed a rapid-access pathway for suspected IBD patients outside of the urgent ‘two-week wait’ criteria, with patients triaged by utilising a combination of FCP results and symptom history.
The researchers suggest that the results from home FCP testing can be coupled with a review of symptoms to form the foundation of effective self-referral pathways. Based on the study findings, patients with two FCPs >200 µg/g could be streamed directly to colonoscopy, while those with two FCPs >100 µg/g could be reviewed in clinic.
A second result ≥220 µg/g is deemed more accurate than dual-result thresholds and can indicate that a patient should be referred directly for a colonoscopy. The researchers observed that only 20% of patients had two samples submitted before referral to secondary care.
Dr Peter Rimmer, academic clinical lecturer in gastroenterology at the University of Birmingham’s National Institute for Health and Care Research (NIHR) Birmingham Biomedical Research Centre (BRC) and corresponding author of the study said: ‘Using a comprehensive 13-point symptom checker and multiple FCP tests, we have been able to identify much more accurately patients who had IBD and other diseases.
‘The rollout of this protocol could reduce the time taken to get a diagnosis and start treatment for IBDs as much more of the screening and testing can be done through primary care. The sensitivity of multiple FCP tests can be used to flag those patients who urgently need referral into secondary care.’
The researchers hope the study will improve referral triage for IBD patients and open new care pathways for them. A large follow-up study will explore the latter.
Efficiencies in the diagnosis of Barrett’s oesophagus have also recently been identified with a successful pilot project using a capsule sponge test found to reduce the need for invasive endoscopy.
