Summary: Researchers have developed a non-invasive urine screening that can identify young children at elevated risk for autism spectrum disorder (ASD) earlier than standard behavioral assessments. The Microbially-Derived Metabolite (MDM) System measures 17 specific small molecules produced by the gut microbiome and uses their concentrations to generate an objective risk score.
In multi-site clinical testing, the MDM System achieved 90% sensitivity and 100% specificity by detecting highly elevated, altered versions of serotonin- and dopamine-related metabolites in the urine of many children with autism. These findings provide biological evidence for a common ASD subtype linked to gut-derived chemicals and support earlier screening and targeted interventions.
Key Facts
- Bypassing the behavioral bottleneck: Current diagnoses rely on behavioral observation, which can delay access to therapy. The MDM urine screen acts as a rapid biological triage to prioritize children who should receive full diagnostic evaluations sooner.
- Neurotransmitter-like metabolites: Corresponding author James Adams and colleagues found that gut microbes in many children with ASD produce metabolites that mimic or alter serotonin and dopamine activity. Because these neurotransmitters influence mood, attention and memory, microbially derived analogs could help explain common co-occurring symptoms such as anxiety and social-communication challenges.
- MDM Scorecard: The MDM System tracks 17 metabolites derived from amino acids including tyrosine, tryptophan and phenylalanine, together with markers of yeast and fungal activity. A child’s personalized MDM score reflects how many of these metabolites exceed established reference ranges.
- Strong performance in trials: Across a sample of 99 children (52 diagnosed with ASD and 47 typically developing) ages 2–11 from four U.S. states, the test detected autism-related metabolic patterns with reported 90% sensitivity and 100% specificity. Many children with ASD showed some metabolite levels 100 to 1,000 times higher than controls, while typically developing children showed no elevated markers on average.
- Proposed ASD-MDM subtype: Because 80–90% of ASD participants exhibited extreme elevations in one or more of the tracked metabolites, the investigators proposed a distinct phenotype called “ASD associated with microbially-derived metabolites” (ASD-MDM). The remaining participants without elevated gut metabolites often had other metabolic or genetic issues.
- Reducing stigma: First author Christina Flynn notes that a measurable, biology-based screen can reframe autism as a condition with observable biological markers, which may reduce parental shame and diagnostic hesitancy and encourage earlier care.
Source: ASU
A simple urine screen may enable earlier identification of children at risk for autism, allowing earlier intervention and potentially better long-term outcomes.
Researchers at Arizona State University and collaborators developed the MDM System to quantify 17 microbially produced metabolites in urine from children aged 2 to 11 years. By measuring these compounds, the team could reliably distinguish many children with autism from typically developing peers in their study groups.
The study’s methods combined semiquantitative and targeted quantitative liquid chromatography–mass spectrometry (LC‑MS) to measure metabolite concentrations. Among the metabolites that distinguished groups were compounds derived from phenylalanine, tryptophan and tyrosine, as well as yeast-associated molecules. Many of these compounds are known to influence neural signaling and can be traced to gut microbial metabolism.
Christina Flynn, the study’s first author, reported that 80–90% of children with ASD had at least one microbially derived metabolite at concentrations above any observed in typically developing children. On average, children with ASD had about three metabolites elevated compared with zero for control children.
James Adams, the corresponding author, emphasized the significance of microbial metabolites that resemble or modify serotonin and dopamine pathways. “These two key neurotransmitters affect mood, cognition and memory,” he said, noting that microbial analogs could contribute to social communication differences, anxiety and attention challenges in some children with ASD.
Although the authors do not claim that these metabolites cause autism, they propose that measuring them provides a useful biological window into a common ASD phenotype and may help guide personalized treatment strategies focused on restoring gut microbial balance where appropriate.
Earlier intervention
Behavior-based diagnoses are essential but often delayed; earlier detection can improve developmental outcomes by enabling prompt behavioral, educational and medical interventions. The MDM urine screen is not a standalone diagnostic test but can function as an efficient triage tool to expedite evaluation and access to services for children at higher biological risk.
Flynn, who is also a parent of a child with autism, said that objective biological markers may reduce feelings of blame or stigma that sometimes deter parents from seeking timely care. “If we can detect risk in urine, families may feel more confident pursuing early evaluation and intervention,” she noted.
A biological window into autism
The metabolites measured by the MDM System originate largely from gut microbes. Many affect neurological pathways linked to serotonin and dopamine, offering a plausible mechanism for how gut chemistry could influence behavior and cognition. The current study aligns with more than 40 prior reports that observed elevated levels of several of these microbial metabolites in children with ASD.
Some preliminary interventions targeting the microbiome have shown reductions in specific metabolites and parallel improvements in gut and behavioral symptoms, but the authors stress that larger, controlled clinical trials are needed before recommending such treatments widely.
Translating the test to practice
The MDM test, developed during Flynn’s doctoral research, is moving toward broader availability and is already being offered by partner laboratories in some regions. For very young children it may serve as a screening or triage tool; for children with an existing diagnosis it can help clinicians investigate underlying biology and monitor response to therapies over time.
Cautious optimism
The research team emphasizes the need for additional validation across larger, more diverse populations to confirm the test’s utility and to clarify how these metabolites relate to autism’s development. Nevertheless, the potential impact is substantial: earlier detection and more personalized care could improve quality of life for individuals and families affected by ASD.
“For many families, one of the biggest challenges is the waiting,” Flynn said. “If this test shortens that gap, even a little, it can make a meaningful difference because early intervention matters.”
Key Questions Answered:
A: The gut and brain communicate through chemical signals. In this study, researchers found that gut microbes in a large portion of children with ASD produce elevated amounts of specific metabolites. These microbial byproducts can enter the bloodstream and be eliminated in urine, offering a non-invasive snapshot of internal biochemical differences.
A: Some gut microbes create molecules that resemble or interfere with neurotransmitters such as serotonin and dopamine, which regulate mood, attention and social memory. When these microbial analogs are abundant, they may affect how brain circuits develop and function, helping to explain certain co-occurring symptoms in some children with ASD.
A: No. The test is not a cure and not a standalone diagnostic. It does, however, identify a biological pattern that could be responsive to targeted biomedical or microbiome-directed approaches in some individuals. Clinical trials so far suggest potential benefits from microbiota-based interventions, but larger, rigorous studies are required before clinical recommendations can be made.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial 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 et al., published in 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
A subset of children with ASD shows unusually high urinary concentrations of microbially-derived metabolites (MDMs), including p-cresol sulfate and indoxyl sulfate. This multi-site study measured many MDMs in the urine of 52 children with ASD and 47 typically developing children aged 2–11 years, using semiquantitative and targeted quantitative LC‑MS. The ASD group had significantly higher concentrations of numerous MDMs. Nearly all children with ASD had one or more MDMs at concentrations above any value observed in the typical group, sometimes by 100–1,000×. Classification based on one or more elevated MDMs yielded 90% sensitivity and 100% specificity. These data suggest a common ASD phenotype defined by elevated microbially-derived metabolites, termed ASD associated with Microbially-Derived Metabolites (ASD-MDM).