Predictive Value of Referral Concerns for Autism Spectrum Disorder and Global Developmental Delay: A Retrospective Audit of a Tertiary Paediatric Developmental Service

AIM: To examine the predictive value of specific concerns documented in paediatric referral letters for subsequent diagnoses of autism spectrum disorder (ASD) and global developmental delay (GDD) within a tertiary child development clinic. METHODS: A retrospective audit was conducted of consecutive children assessed at the Nepean Hospital Child Development Clinic between 2015 and 2019. Referral letters, supporting documents, and medical records were reviewed to identify referral concerns and diagnostic outcomes. Chi-square analyses were used to explore associations between referral concerns and final diagnoses. RESULTS: Among 161 children assessed, 68% were under 5 years of age, and 78% were male. Speech delay (80%) and social interaction concerns (78%) were the most frequently documented referral issues. Following multidisciplinary assessment, 51% of children referred for ASD were diagnosed with ASD, and 57% referred for developmental concerns were diagnosed with GDD. Speech delay was the only referral concern significantly associated with an ASD diagnosis (p = 0.002). Behavioural concerns predicted attention deficit hyperactivity disorder (ADHD) and GDD (p < 0.001), while motor delay predicted GDD (p < 0.05). ADHD, although not a primary focus of the clinic during the study period, emerged as a clinically relevant co-occurring outcome. Ten percent of children received no neurodevelopmental diagnosis. CONCLUSIONS: Referral concerns varied widely in their diagnostic utility. Speech delay demonstrated the strongest predictive value for ASD, while motor delay and behavioural problems were associated with GDD. Other commonly cited concerns lacked diagnostic specificity. These findings highlight the clinical value of detailed symptom-based referral information and support the role of early speech pathology assessment in improving triage and prioritisation for ASD within tertiary developmental services.