The number of patients referred to the hospital for an unnecessary endoscopy could be cut by nearly a third if an additional test that can be carried out by a GP could be incorporated, according to new research published in the open access journal BMC Medicine.

This new diagnostic strategy for patients suspected of serious colorectal disease (SCD) was developed by researchers based at hospitals across the Netherlands. Their study showed that SCD can be more accurately excluded at the GP's clinic if the doctor carries out an additional test, and so reduce the number of people requiring an invasive endoscopy.

Serious colorectal diseases, including colorectal cancer, are difficult to diagnose as the signs and symptoms are not always clear. Any suspicion of SCD requires a GP referral to a hospital for an endoscopy but studies have shown that between 60-80% of referred patients end up not having SCD.

Dr Sjoerd Elias, corresponding author from the Julius Centre for Health Sciences and Primary Care at the University Medical Center in Utrecht, said: "The amount of patients that are unnecessarily referred for an endoscopy strains health care budgets and exposes patients to a small but realistic risk from endoscopy associated complications. Our study found that using a test called FIT, which detects the presence of haemoglobin in the patient's faeces, alongside the usual diagnostic work up done by GPs could rule out nearly a third of patients from requiring an endoscopy to check for SCD."

The research uses data collected from the large-scale CEDAR study where 810 patients suspected of SCD were enrolled from 266 primary care practices in the Netherlands. All the patients were subjected to FIT before being referred for an endoscopy. FIT is a well-established test that is already used as a basis for colorectal cancer screening. The test uses an antibody that recognizes human haemoglobin and so can be used to detect the presence of blood in a patients stool sample.

Out of the 810 patients referred for an endoscopy, 669 were found to have no SCD. Once the results of the FIT test had been taken into account the researchers found that approximately 30% of these patients could have been prevented from having an endoscopy as they may have been correctly diagnosed as not having SCD during their GP visit.

The study also looked at the benefit of adding a faecal test for the protein calprotectin to the diagnostic strategy. They found that this test also improved the diagnosis of SCD but not to the same extent as FIT. Furthermore, combining both tests added little extra benefit to the diagnostic accuracy of FIT alone.

The authors note that while the addition of FIT could be able to substantially reduce the number of unnecessary endoscopy referrals, there is still a small risk that some patients with SCD will be misdiagnosed and not referred for the procedure. In this study, one patient with colorectal cancer would not have been selected for endoscopy referral. However, the authors say that in such cases careful monitoring for persistent symptoms would delay rather than miss the diagnosis.

Article: Is there an added value of faecal calprotectin and haemoglobin in the diagnostic work-up for primary care patients suspected of significant colorectal disease? A cross-sectional diagnostic study, Sjoerd G. Elias, Liselotte Kok, Niek J. de Wit, Ben J. M Witteman, Jelle G. Goedhard, Mariëlle J. L. Romberg-Camps, Jean W. M. Muris and Karel G. M. Moons, BMC Medicine, doi: 10.1186/s12916-016-0684-5, published 26 September 2016.