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Screening & Evaluation

Screening & Evaluation

Screening tools, milestone checklists and official guidance on how autism is identified — from well-child checkups to a full diagnostic evaluation.

Based on CDC · AAP HealthyChildren.org · Autism Society · CPIR · All sources · Checked November 3, 2026

9 · 18 · 30months: general developmental screening at well-child visitsAAP, as described by CDC
Age 2a diagnosis by an experienced professional is considered reliableCDC
Not a diagnosisa positive screen means a full evaluation is neededAAP HealthyChildren · CDC

Monitoring, screening, then evaluation

Families track milestones at home, a health or early-childhood professional does a formal screening, and a team of specialists does a diagnostic evaluation if a closer look is needed. The resources below are the official sources for each step. Listings link to external organizations; they do not imply affiliation, endorsement or guaranteed services, and eligibility, availability and costs change — confirm directly with each organization.

Milestones and screening ages

Federal agencyCDC — Developmental MilestonesFree CDC milestone checklists from 2 months through 5 years, available to print, complete online or in the Milestone Tracker app; the page notes checklists do not replace standardized developmental screening at 9, 18 and 30 months and autism screening at 18 and 24 months.Visit official resource Federal agencyCDC — Act Early resources for familiesCDC tools for families — the Milestone Tracker app, milestone checklists, developmental screening options, children’s books and parenting tips — plus the National Maternal Mental Health Hotline for parents who need support.Visit official resource Federal agencyCDC — Clinical Screening for Autism Spectrum DisorderCDC’s page for health care providers on screening tools (such as the Ages and Stages Questionnaires, the M-CHAT and the STAT) and the AAP-recommended screening schedule; useful for understanding what your child’s doctor is using.Visit official resource NonprofitAAP HealthyChildren.org — How Pediatricians Screen for AutismFrom the American Academy of Pediatrics: formal autism screening for all children at 18 and 24 months, with the M-CHAT-R/F the most common tool; screening should also happen whenever parents raise concerns, and a positive screen is not a diagnosis.Visit official resource

Signs that prompt a closer look

NonprofitAAP HealthyChildren.org — 3 Early Signs of Autism in ChildrenDescribes early differences in joint attention — such as not looking where a parent points by 12 months or pointing to get things rather than to share interest by 18 months — and urges families not to wait to talk with their pediatrician.Visit official resource Federal agencyCDC — Screening and Diagnosis of Autism Spectrum DisorderCDC’s overview of how autism is identified: developmental monitoring by families, formal screening by professionals, and diagnostic evaluation by specialists; autism can sometimes be detected by 18 months, and a diagnosis by age 2 is considered reliable.Visit official resource NonprofitAutism Society — Screening & DiagnosisThe Autism Society explains the difference between a medical diagnosis (made by specialists using the DSM-5) and an educational determination (made by school teams under IDEA), and lists common co-occurring conditions to discuss with providers.Visit official resource

Requesting an evaluation

Federal agencyCDC — Concerned About Your Child’s Development?What to say and whom to call: under 3, your local early intervention system; 3 and older, a local public elementary school. You do not need a referral or diagnosis to request a free evaluation.Visit official resource NonprofitCPIR — Evaluating Children for DisabilityHow parents request a school evaluation, the requirement for written consent and prior written notice, the 60-day evaluation timeline (unless the state sets its own), and re-evaluation at least every three years.Visit official resource

Questions to ask

  • Which screening tool was used, and what did the result mean?
  • If the screen was positive, who will do the full evaluation and how soon?
  • Can my child be screened again now, even if the next checkup is months away?
  • Does the evaluation cost anything, and what will insurance cover?

This website provides general educational information. It does not diagnose autism or replace individualized medical, developmental, psychological, or educational advice. Screening is not diagnosis.

External listings do not imply affiliation, endorsement, or guaranteed services. Eligibility, availability, costs, and insurance coverage may change. Research summaries reflect evidence available at the time of review.