Stool test 'accurate for diagnosing bowel diseases'
UK scientists say they have found a way of diagnosing different types of bowel disease by testing the smells given off by patients' stools.
The test analyses the chemical compounds emitted and recognises the profile of different diseases.
In a study of 182 stool samples from patients with inflammatory bowel disease and irritable bowel syndrome, the results were 76% accurate.
The research team said the test could provide more accurate diagnoses.
The University of the West of England study, published in the Journal of Breath Research, used a testing system they built combining a gas chromatograph and a metal oxide sensor to recognise patterns specific to known diseases.
These patterns are created by volatile organic compounds emitted from stool samples, which are a good indicator of the conditions in the patient's gastrointestinal tract.
Difficult to diagnose
Norman Ratcliffe, professor of material and sensor sciences at UWE, said their specially-designed 'odour reader' would get even more accurate results with more samples to test.
"There is a huge amount of variation in samples because of the different foods eaten by patients, but we have trained the system to match unknown samples to the database of patterns it has already acquired. With more samples, we would get better results."
The method could be particularly useful for diagnosing a group of diseases that are hard to distinguish, he said.
Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), for example, have very similar symptoms, making a definitive diagnosis difficult - and yet they are very different conditions.
IBD is an autoimmune disease caused by a response of the immune system to microbes in the gut, which is usually diagnosed by colonoscopy, while IBS is a disorder of the digestive tract with no known cause.
It is often only diagnosed when other more serious bowel diseases have been ruled out.
The study results also showed that patients with IBD could be distinguished from healthy patients with a 79% accuracy.
Gary Douch, chairman of Bowel Disease UK, said the process offered hope to those suffering from a range of bowel diseases.
"If this process is as accurate as 76% it will offer hope to those potentially suffering from IBD.
"If patients can be correctly diagnosed early without the invasive investigations, it will save the NHS money and also speed up much-needed treatment for the patient."