More resources about Understanding Autism Spectrum Disorder (ASD)More resources about Understanding Autism Spectrum Disorder (ASD)

How is Autism Diagnosed?

This guide is your go-to resource for understanding how Autism Spectrum Disorder (ASD) is diagnosed. From what early signs to look for, to who does the diagnosing, to what all those acronyms like ADOS and DSM-5 actually mean—we’ve got you covered.

Understanding how Autism Spectrum Disorder (ASD) is diagnosed can be overwhelming for families, especially when they’re just starting their journey. This guide breaks down the essential information in a clear, family-friendly way.

What is Autism Spectrum Disorder (ASD)?

ASD is a developmental condition that affects communication, behavior, and social interaction. Because autism is a spectrum, symptoms and severity can vary widely from one person to another.

Why an Early Autism Diagnosis is Important

Early diagnosis helps children access early intervention services, which can significantly improve outcomes in communication, behavior, and daily living skills.

Who Can Diagnose Autism?

Autism is typically diagnosed by:

  • Developmental pediatricians
  • Child psychologists or psychiatrists
  • Pediatric neurologists

These specialists use standardized tools, observations, and input from parents, teachers, and caregivers.

Steps in the Autism Diagnosis Process

  1. Developmental Screening: Usually done during well-child visits at 18 and 24 months.
    1. The M-CHAT-R is a tool that parents can fill out as an important first step in identifying potential signs of ASD
  2. Comprehensive Diagnostic Evaluation: If screening raises concerns, a full evaluation follows.
  3. Medical and Family History: Helps rule out other conditions.
  4. Behavioral Observation: Observing the child in different settings.
  5. Standardized Tests: Like ADOS (Autism Diagnostic Observation Schedule) or CARS (Childhood Autism Rating Scale).

DSM-5 Autism Criteria Checklist

The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Edition) outlines specific criteria that professionals use to diagnose ASD.

Domain A: Persistent deficits in social communication and social interaction, including:

  • Difficulty with back-and-forth conversation
  • Trouble understanding nonverbal communication (e.g., eye contact, gestures)
  • Difficulty developing, maintaining, or understanding relationships

Domain B: Restricted, repetitive patterns of behavior, interests, or activities, such as:

  • Repetitive motor movements or speech (e.g., hand-flapping, echolalia)
  • Insistence on sameness, routines, or rituals
  • Intense or highly focused interests
  • Hyper- or hypo-reactivity to sensory input (e.g., sensitivity to sounds or textures)

Note: Symptoms must be present in early developmental stages, cause significant impairment, and not be better explained by intellectual disability or global developmental delay.

What Parents Should Watch For

Common early signs of autism include:

  • Lack of eye contact
  • Delayed speech or language skills
  • Limited interest in peers
  • Repetitive behaviors (rocking, spinning)
  • Strong reactions to sensory input

Common Questions About Autism Diagnosis

Is there a blood test or brain scan for autism?No. Autism is diagnosed based on behavior and developmental history, not medical tests.

Can a child be diagnosed after age 3?Yes, though early detection is ideal, some children may not show clear signs until later.

Getting Support After Diagnosis

After an autism diagnosis, families can explore:

Final Thoughts

Understanding how ASD is diagnosed empowers parents to take informed steps toward early support. If you have concerns about your child’s development, speak with your pediatrician or one of our in-house diagnosticians about an autism evaluation.