Summary: Researchers introduced a non-invasive urine test that can identify young children at high risk for autism spectrum disorder (ASD) far sooner than traditional behavioral assessments. The research debuts the Microbially-Derived Metabolite (MDM) System, a screening tool that measures 17 specific small molecules produced by the gut microbiome.
In clinical trials across multiple states, the test achieved 90% sensitivity and 100% specificity by detecting heavily elevated, altered versions of serotonin and dopamine in the urine of children with autism, providing clear biological validation for the condition and paving the way for early, life-changing interventions.
Key Facts
- The Behavioral Bottleneck Overridden: Current autism diagnostic protocols depend entirely on subjective behavioral observations, which frequently saddle families with long, stressful wait times before they can access early therapeutic support. This new urine screen functions as a rapid biological triage tool to move high-risk children to the front of the line for clinical evaluation.
- The Neurotransmitter Mimics: Corresponding author Dr. James Adams noted a striking molecular phenomenon: the gut bacteria in children with autism manufacture metabolites that act as altered versions of serotonin and Dopamine. Because these two master neurotransmitters govern mood, cognition, focus, and memory, their microbial corruption offers a direct biological explanation for common co-occurring symptoms like anxiety, depression, and social communication barriers.
- The MDM Scorecard: The newly engineered Microbially-Derived Metabolite (MDM) System tracks compounds derived from tyrosine, tryptophan, and phenylalanine (amino acids critical to brain signaling pathways), alongside markers of yeast and fungal activity. The system assigns a personalized risk score based on how many of these 17 tracked molecules exceed standard reference ranges.
- Flawless Specificity in Trials: Testing a cohort of 92 children ages 2 to 11 across Arizona, Massachusetts, Tennessee, and Texas, the test demonstrated a staggering 90% sensitivity and 100% specificity. Nearly all children with autism presented at least one metabolite level measuring 100 to 1,000 times higher than the control group, while typically developing children averaged zero elevated markers.
- The ASD-MDM Phenotype: Based on the fact that 80% to 90% of autistic subjects displayed extremely high levels of these specific compounds, the researchers have proposed a brand-new clinical subtype of autism called “ASD associated with microbially-derived metabolites” (ASD-MDM). The remaining 10% without gut imbalances typically presented alternative metabolic issues tied to separate genetic disorders.
- Erasing Parental Stigma: First author Dr. Christina Flynn, a parent of an autistic child, stresses that proving autism can be detected through a simple urine test reframes it as a concrete, biology-based condition. This physical validation helps dissolve the groundless shame or “bad parenting” stigma that often causes diagnostic hesitancy in families.
Source: ASU
A simple urine test may help identify children at risk for autism sooner than current assessments — opening the door for earlier diagnosis and treatment, and better long-term outcomes for children who do have autism spectrum disorder.
Arizona State University scientists and their collaborators have developed a new screening tool to test urine for 17 microbial metabolites — small molecules produced by microorganisms in the gut — in children ages 2 to 11 years.
By measuring these compounds in urine, the team discovered that they could distinguish children with autism from typically developing children in their study groups with high accuracy.
And understanding the biological diversity within autism could help guide more targeted interventions, including approaches aimed at restoring a healthy gut microbiome.
The research, published today in Molecular Psychiatry, points to a consistent biological pattern in many children with autism — elevated levels of specific metabolites in the gut.
These included metabolites that come from tyrosine, tryptophan and phenylalanine — amino acids involved in key neurotransmitter pathways — as well as other compounds connected to yeast and fungal activity.
The new classification tool is called the “Microbially-Derived Metabolite (MDM) System.” The system assigns a score based on how many metabolites in a child’s urine exceed a typical reference range.
“What we’ve discovered is that 80 to 90% of children with autism have extremely high levels of one or more microbially derived metabolites,” said Christina Flynn, first author of the study and a recent ASU PhD graduate. “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.”
Flynn completed her doctoral studies in chemical engineering in December through the Ira A. Fulton Schools of Engineering at ASU. Her research is part of work through the Biodesign Center for Health Through Microbiomes in the Biodesign Institute at ASU. She is now the research director for the newly launched CLIA-certified Autism Diagnostics Laboratory and serves as a senior research scientist for Gut Brain Axis Therapeutics.
During trials, the urine test showed promising accuracy, with 90% sensitivity and 100% specificity. That means it correctly identified 90% of the children with autism, and did not misidentify any of the children without autism in the study.
Additional confirmation of the test’s accuracy is underway to further validate the test due to the moderate sample size of the study.
Using advanced research techniques, the team measured the concentration of microbially-derived metabolites in 52 children diagnosed with autism spectrum disorder, and 47 typically developing children ages 2 to 11 years. Children from four geographic locations, including Arizona, Massachusetts, Tennessee and Texas, participated in the study.
The differences were clear: Nearly all children with autism had at least one metabolite level exceeding the highest observed in the control group, with some levels measuring 100 to 1,000 times higher. On average, children with autism spectrum disorder had about three elevated metabolites, while typically developing children had none.
“What’s really striking about the bacteria is that they make metabolites that are basically altered versions of serotonin and dopamine,” said President’s Professor James Adams, corresponding author of the study and a researcher with the Biodesign Center for Health Through Microbiomes.
“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,” he said. Adams is also the father of an adult daughter with autism.
“We think reducing the levels of these metabolites may help these children lead healthier and happier lives, and we encourage children to be screened sooner to receive earlier interventions,” said Adams, also with the School of Engineering of Matter, Transport and Energy, part of the Ira A. Fulton Schools of Engineering.
Earlier intervention
Current diagnostic tests depend on behavioral observations, and many families face long wait times for answers. Better developmental outcomes are linked to earlier identification and earlier intervention, whether medical, behavioral or educational.
“We hope there is a reduction in stigma and shame associated with the condition,” said Flynn, who herself is a parent of a child with autism. “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. Hopefully that will prevent any hesitancy on parents’ parts to seek treatment and seek it as early as possible.”
While the urine test is not a stand-alone diagnosis, the researchers say this can help move children to the front of the line for evaluation and specific support.
A biological window into autism
Beyond screening, the findings also point to a possible biological pathway involved in many cases of autism. The metabolites measured in the test are largely produced by the gut microbiome. Some are known to affect the brain and are linked to neurotransmitters including serotonin and dopamine, which play key roles in mood, cognition and behavior.
This study is consistent with over 40 other studies which have found that many of the microbial metabolites measured in the MDM System are significantly higher in children with autism.
The team cautions that their research does not prove these metabolites cause autism, even though some of them are strongly associated with symptoms associated with the disorder.
And based on their findings, the researchers propose a new subtype of autism called “ASD associated with microbially-derived metabolites,” or ASD-MDM. This phenotype encompasses about 90% of cases of autism spectrum disorder. Approximately 10% of children with autism in the study did not have abnormal gut metabolites, however, most of those children had other major metabolic problems possibly associated with genetic disorders.
“For more than 15 years, I have been doing research on the gut microbiome and its potential contributions to human health, and autism spectrum disorder has been at the core of our research,” said Professor Rosa Krajmalnik-Brown, co-author of the study.
“I am excited about the MDM test, which includes important microbial metabolites, previously hypothesized to be linked with autism. This test can be a great way to assess this important microbial contribution,” said Krajmalnik-Brown, director of the Biodesign Center for Health Through Microbiomes at ASU.
Some preliminary research suggests that interventions such as microbiota-based therapies may influence metabolite levels and improve symptoms in certain individuals. For example, the team’s first clinical trial of microbiota transplant therapy found that the treatment resulted in a substantial decrease in one microbial metabolite, p-cresol sulfate, accompanied by substantial improvements in gut symptoms and behavioral symptoms. However, the authors emphasize that more rigorous clinical trials are needed before such approaches can be widely recommended.
From the lab to real-world use
The test, developed as part of Flynn’s doctoral research, is moving toward broader availability. Analutos, a partner lab in the United Kingdom, is already offering the urine test internationally.
For younger children, the test may serve as a triage tool. For those already diagnosed, it may help clinicians explore underlying biological factors and monitor how interventions affect the body over time.
Cautious optimism
The researchers stress that more studies are needed to validate the findings across larger and more diverse populations, and to better understand how these metabolites are related to the development of autism.
Still, the potential impact is significant.
Autism affects an estimated 1 in 31 children in the United States, and the lifetime cost of care averages $3.6 million per person.
Earlier detection and more personalized approaches could help improve quality of life — not just for individuals, but for entire families.
“For many families, one of the biggest challenges is the waiting — the not knowing,” Flynn said. “If this test shortens that gap, even by a little, that’s meaningful because earlier intervention can really help.”
Key Questions Answered:
A: Because your gut and your brain are constantly talking to each other through chemical signals. The researchers at Arizona State University discovered that the gut microorganisms in 80% to 90% of children with autism produce massive amounts of specific chemical byproducts. When these microbial molecules spill over into the bloodstream, they are eventually filtered out into the urine, giving scientists a pristine, non-invasive look at the child’s internal biological environment.
A: The bacteria in an autistic child’s gut are actively creating altered, warped versions of serotonin and dopamine, the two primary neurotransmitters responsible for regulating mood, attention, and social memory. When these hijacked chemical look-alikes flood a developing child’s system, they can directly interfere with how brain cells talk to one another, which beautifully explains the biological roots behind co-occurring symptoms like anxiety and attention issues.
A: The test is not a stand-alone diagnostic tool or a direct cure, but it opens a massive window for targeted biomedical support. While the team emphasizes that these metabolites aren’t proven to cause autism, preliminary clinical trials showed that balancing the gut microbiome via microbiota transplant therapies caused a massive drop in toxic metabolites like p-cresol sulfate, which was accompanied by major improvements in both digestive and behavioral symptoms.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this autism research news
Author: Sandy Keaton Leander
Source: ASU
Contact: Sandy Keaton Leander – ASU
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Elevated microbially-derived metabolites in autism: a possible diagnostic screening test for a distinct ASD phenotype” by Christina K. Flynn, Kevin Carr, Paul Whiteley, Khemlal Nirmalkar, Andrew Bellinghiere, Juergen Hahn, Hongbin Liu, Halil Arici, Laura Hewitson, Morgan Devlin, Elena L. Pollard, Khyatiben V. Pathak, Krystine Garcia Mansfield, Anakaren Rosales Torres, Patrick Pirrotte, Daniel B. Kalb, Rebekah Keen, Victoria Kenyon, Alessio Fasano, Rosa Krajmalnik-Brown, James B. Adams & Sarah Kadzielski. Molecular Psychiatry
DOI:10.1038/s41380-026-03620-5
Abstract
Elevated microbially-derived metabolites in autism: a possible diagnostic screening test for a distinct ASD phenotype
Many studies have confirmed that a subset of children with autism spectrum disorder (ASD) have unusually high urinary concentrations of microbially-derived metabolites (MDMs) such as p-cresol sulfate and indoxyl sulfate. We hypothesized that these MDMs may affect neurodevelopment through the gut-brain axis and that a sub-phenotype characterized by gut dysbiosis may be present in most ASD individuals.
This multi-site study involved measuring the concentrations of many MDMs in the urine of 52 children with ASD and 47 healthy, typically developing (TD) children, aged 2 to 11 years. The measurements were conducted first with semiquantitative Liquid Chromatography and Mass Spectrometry (LC-MS), followed by targeted quantitative LC-MS. The ASD group had significantly higher concentrations of many MDMs compared to the TD group.
The MDMs included phenylalanine-derived, tryptophan-derived, and yeast-derived MDMs. Almost all children with ASD had one or more MDMs at concentrations above any TD child, and sometimes 100–1000× higher. The children with ASD had an average of 3 MDMs at levels above any TD child, compared to zero (by definition) for the TD children.
Classification using one or more elevated MDM yielded a sensitivity of 90% and a specificity of 100%. This MDM SystemTM is a promising non-invasive method for diagnostic screening for ASD in children ages 2 to 11 years.
These data also suggest approximately 90% of children with ASD have a distinct phenotype of ASD, which we propose naming ASD associated with Microbially-Derived Metabolites (ASD-MDM), defined by objective, quantitative laboratory measurements of these metabolites in urine.
