A groundbreaking new study suggests that a simple urine test could detect autism spectrum disorder (ASD) earlier and more accurately than traditional screening methods. With autism now affecting 1 in 31 children in the United States—a dramatic rise from 1 in 150 in the early 2000s—researchers are urgently seeking better diagnostic tools and potential causes.
Current Diagnostic Challenges
Traditionally, autism diagnosis relies on questionnaires, observational assessments, and cognitive tests, a process that can take months or even years. This delay often postpones crucial early interventions that can improve outcomes for children with autism.
The New Urine Test
Scientists at Arizona State University have developed a urine test that screens for 17 microbial metabolites—molecules produced by gut microorganisms. Their findings, published in the journal Molecular Psychiatry, show that up to 90% of children with autism have extremely high levels of these metabolites in their urine. The test accurately distinguished autistic children from neurotypical peers with about 90% accuracy, requiring just a single sample.
The researchers believe these metabolites are altered versions of the neurotransmitters serotonin and dopamine, which regulate mood, cognition, and memory. Disruptions in these chemicals may contribute to autistic behaviours such as social and communication difficulties.
Study Details
The study involved 52 children with autism and 47 neurotypical children, aged 2 to 11, from Arizona, Massachusetts, Tennessee, and Texas. Most participants were from Arizona, and the majority of autistic children were boys. The team analysed 17 metabolites, finding six significantly higher in the autistic group—ranging from 29% to 228% higher. Eight tryptophan-derived metabolites were 38% to 1,882% higher in autistic children. On average, autistic children had three elevated metabolites, while typically developing children had none.
Implications for Diagnosis and Treatment
Lead author Christina Flynn, a recent Arizona State University PhD graduate, stated: 'What we've discovered is that 80 to 90 percent of children with autism have extremely high levels of one or more microbially derived metabolites. Using this test will tell you which young children are at high risk for being diagnosed with autism, and guide treatment in those who have already been diagnosed to help them lead their best lives.'
Corresponding author James Adams, a professor at Arizona State University, added: 'What's really striking about the bacteria is that they make metabolites that are basically altered versions of serotonin and dopamine. These are two key neurotransmitters that affect mood, cognition and memory. This could explain many of the symptoms and co-occurring symptoms in children with autism—their social communication, anxiety, depression and attention. We think reducing the levels of these metabolites may help these children lead healthier and happier lives.'
A New Subtype of Autism
The findings propose a new autism subtype called 'ASD associated with microbially-derived metabolites' (ASD-MDM), which may encompass 90% of cases. Preliminary research suggests that microbiota-based therapies, such as fecal transplants, prebiotics, and probiotics, might reduce metabolite levels and improve autistic behaviours, though further studies are needed.
Flynn emphasised the emotional impact: 'For many families, one of the biggest challenges is the waiting—the not knowing. If this test shortens that gap, even by a little, that's meaningful because earlier intervention can really help.' She also hopes the test reduces stigma: 'Sometimes diagnostic hesitancy happens because parents feel like they're not good enough parents and they're being judged. But that's not the case because if we can detect it in urine, it's a biology-based condition.'
