Could autism one day be diagnosed with a urine test?

Some British researchers think it might be a possibility, after they discovered what they say is a unique chemical fingerprint in the urine of children with the condition.

Autism is sometimes difficult to diagnose as it can be confused with other behaviour-related problems. Children are usually assessed through social interaction and communication tests, but most kids aren't diagnosed until their preschool years and sometimes even much later.

Because the parents of children with autism often report that their children suffer from distinct gastrointestinal problems, one theory is that autistic children have a unique bacterial makeup in their intestines.

Now researchers say it is possible to distinguish between autistic and non-autistic children by looking at the by-products of their intestinal bacteria and the body's metabolic processes in the children's urine.

Using spectroscopy, lead researcher Jeremy Nicholson, a professor at Imperial College London, and colleagues from the University of South Australia analyzed the urine in about 100 children, aged three to nine, who were broken into three groups: those diagnosed with autism, non-autistic siblings of children with autism, and a control group with no history of autism in the family.

They found that each group had an internally consistent chemical fingerprint that was distinct from the other two groups.

Their results are published in the Journal of Proteome Research.

If researchers can isolate the distinct chemical marker in the urine of autistic children, that opens the door for a new way to test for the condition.

"Such a test could take many years to develop and we're just beginning to explore the possibilities," Nicholson said in a news release, adding it would be exciting to be able to create a test to allow for earlier diagnosis.

"We know that giving therapy to children with autism when they are very young can make a huge difference to their progress. A urine test might enable professionals to quickly identify children with autism and help them early on," he said.

The researchers are now keen to investigate whether metabolic differences in people with autism are related to the causes of autism or are a consequence of its progression.

In an email to CTV News, Nicholson said if all goes well with further research, a test might be ready for testing in three to five years.