At what ages is autism spectrum disorder screening recommended, and which tool is most commonly used?

• A. 18 and 24 or 30 months; M-CHAT-R/F
• B. At birth; M-CHAT
• C. 12 months only; ASQ
• D. 3-4 years; STAT

Answer: (D)

Autism screening is recommended during the toddler years, specifically around 18 months and again near 24 months, using a validated instrument designed for early identification. The most commonly used tool is the M-CHAT-R/F, which starts as a parent-completed questionnaire and includes a follow-up interview if the initial screen raises concerns. This two-step approach helps flag children who may benefit from a formal diagnostic evaluation without overcalling typical development. Screening at birth or only at 12 months isn’t recommended for autism specifically, and tools like ASQ are developmental screens (not autism-specific) while the STAT is another autism-related screen but not the one most routinely used in primary care. When the screen is positive, a comprehensive assessment is pursued to confirm the diagnosis and plan early intervention.