There are many tools to assess ASD in young children, but no single tool should be used as the basis for diagnosis. Diagnostic tools usually rely on two main sources of information - parents' or caregivers' descriptions of their child's development and a professional's observation of the child's behavior.
In some cases, the primary care provider might choose to refer the child and family to a specialist for further assessment and diagnosis. Such specialists include neurodevelopmental pediatricians, developmental-behavioral pediatricians, child neurologists, geneticists, and early intervention programs that provide assessment services.
Selected examples of diagnostic tools:
Autism Diagnosis Interview - Revised (ADI-R) - A clinical diagnostic instrument for assessing autism in children and adults. The instrument focuses on behavior in three main areas: reciprocal social interaction; communication and language; and restricted and repetitive, stereotyped interests and behaviors. The ADI-R is appropriate for children and adults with mental ages about 18 months and above.
Autism Diagnostic Observation Schedule - Generic (ADOS-G) - A semi-structured, standardized assessment of social interaction, communication, play, and imaginative use of materials for individuals suspected of having ASD. The observational schedule consists of four 30-minute modules, each designed to be administered to different individuals according to their level of expressive language.
Childhood Autism Rating Scale (CARS) - Brief assessment suitable for use with any child over 2 years of age. CARS includes items drawn from five prominent systems for diagnosing autism; each item covers a particular characteristic, ability, or behavior.
Gilliam Autism Rating Scale - Second Edition (GARS-2) - Assists teachers, parents, and clinicians in identifying and diagnosing autism in individuals ages 3 through 22. It also helps estimate the severity of the child's disorder.
There are many different developmental screening tools. This list is not exhaustive, and other tests may be available.
Selected examples of screening tools for general development and ASD:
Ages and Stages Questionnaires (ASQ) - This is a general developmental screening tool. Parent-completed questionnaire; series of 19 age-specific questionnaires screening communication, gross motor, fine motor, problem-solving, and personal adaptive skills; results in a pass/fail score for domains.
Communication and Symbolic Behavior Scales (CSBS) - Standardized tool for screening of communication and symbolic abilities up to the 24-month level; the Infant Toddler Checklist is a 1-page, parent-completed screening tool.
Parents' Evaluation of Developmental Status (PEDS) - This is a general developmental screening tool. Parent-interview form; screens for developmental and behavioral problems needing further evaluation; single response form used for all ages; may be useful as a surveillance tool.
Modified Checklist for Autism in Toddlers (MCHAT) - Parent-completed questionnaire designed to identify children at risk for autism in the general population.
Screening Tool for Autism in Toddlers and Young Children (STAT) - This is an interactive screening tool designed for children when developmental concerns are suspected. It consists of 12 activities assessing play, communication, and imitation skills and takes 20 minutes to administer.