BOSTON, April 24, 2026 – A new study examined geographic patterns in autism diagnosis by primary care providers among Medicaid-enrolled children in 29 states. The study found that Nevada, South Carolina and Connecticut had the highest rates of autism diagnosis by primary care providers. Findings from the study will be presented at the Pediatric Academic Societies (PAS) 2026 Meeting , taking place April 24-27 in Boston. This study is part of a larger research project, Addressing Structural Disparities in Autism Spectrum Disorder through Analysis of Secondary Data (ASD3) , which is funded by the National Institutes of Health.
An autism spectrum disorder (ASD) diagnosis by a medical provider is often required for disability and therapy services access. Given long wait times and limited access to specialty care providers who typically diagnose ASD, some states have expanded primary care provider ASD diagnostic training. Yet little research has examined geographic patterns in primary care providers ASD diagnosis.
"Autism is typically diagnosed by specialists, but various factors such as long wait times can delay this process," said the ASD3 investigative team. "Primary care providers can offer an additional pathway to early diagnosis, which is important for improving access to needed autism services and supports. Our study looked at Medicaid-enrolled children ages 1-5 in 29 states between 2017-2019, and found that 29% were diagnosed by primary care providers rather than specialists. Rates of autism diagnosis by primary care providers varied significantly between counties, states and regions. We believe that local practice patterns and specialist availability may contribute to this geographic variation."
The sample included 36,263 children across 933 county-sets in 29 states. Overall, 29% of children were diagnosed with ASD by a primary care provider. Regional percentages varied from a median of 20.0% among county-sets in the Midwest to 36.4% in the West. Within-region variation was also high, with interquartile ranges (IQRs) varying from 23.8% in the Midwest to 27.5% in the West. Within-region variation was also high when grouping county-sets by state. For example, the Northeast had both the third highest state (Connecticut, 53.1%) and the third lowest state (New Hampshire, 14.3%) as measured by their median county-set. The neighboring states of South Carolina (60.4%) and Georgia (17.9%), both in the South region, ranked second highest and fifth lowest, respectively. Within-state heterogeneity (IQR) was as low as 6.2% (Connecticut), 9.6% (New Hampshire), and 12.7% (Georgia) and as high as 35.7% (Colorado), 37.6% (Illinois), and 42.3% (Wyoming). Population density showed a slight trend with the densest quartile of county-sets having a median primary care provider diagnosis rate of 24.2%, and 28.6% for the least dense quartile.
Additional information is included in the below research abstract. The PAS Meeting connects thousands of leading pediatric researchers, clinicians and educators worldwide. View the full schedule in the PAS 2026 program guide
