Diagnostic Accuracy of Primary Care Clinicians Across a Statewide System of Autism Evaluation.

Objectives: To evaluate the diagnostic accuracy of the Early Autism Evaluation (EAE) Hub system, a statewide network that provides specialized training and collaborative support to community primary care providers in the diagnosis of young children at risk for autism spectrum disorder (ASD).

Methods: EAE Hub clinicians referred children, aged 14 to 48 months, to this prospective diagnostic study for blinded follow-up expert evaluation including assessment of developmental level, adaptive behavior, and ASD symptom severity. The primary outcome was agreement on categorical ASD diagnosis between EAE Hub clinician (index diagnosis) and ASD expert (reference standard).

Results: Among 126 children (mean age: 2.6 years; 77% male; 14% Latinx; 66% non-Latinx white), 82% (n = 103) had consistent ASD outcomes between the index and reference evaluation. Sensitivity was 81.5%, specificity was 82.4%, positive predictive value was 92.6%, and negative predictive value was 62.2%. There was no difference in accuracy by EAE Hub clinician or site. Across measures of development, there were significant differences between true positive and false negative (FN) cases (all Ps < .001; Cohen's d = 1.1-1.4), with true positive cases evidencing greater impairment.

Conclusions: Community-based primary care clinicians who receive specialty training can make accurate ASD diagnoses in most cases. Diagnostic disagreements were predominately FN cases in which EAE Hub clinicians had difficulty differentiating ASD and global developmental delay. FN cases were associated with a differential diagnostic and phenotypic profile. This research has significant implications for the development of future population health solutions that address ASD diagnostic delays.