Autism Screening & Diagnosis

There is no medical autism test, like a blood test, to diagnose autism spectrum disorder (ASD). Instead, experienced medical professionals examine a person’s developmental history and behavior, interview and observe the person and their loved ones, and use professional screening and diagnostic tools to make a diagnosis. While an autism diagnosis can only be given by a health care professional, there are several screening tools that can alert parents, caregivers and autistic people to potential autism symptoms. Early screening for autism can impact access to services and supports, which in turn can influence future outcomes for autistic individuals.

What is autism screening?

Autism screening is a more formal process of looking at aspects of a child’s development to detect early potential signs of autism. In autism screening, a parent or caregiver usually answers questions about how a child moves, plays, speaks, and interacts with others.

When does autism screening usually happen?

Autism screening can happen at a well-child health visit or when a parent, caregiver, educator, or health professional feels concerned. The AAP recommends autism screening at 18 months and 24 months. If screening shows there are delays in important milestones, caregivers may decide to watch and wait, or they may decide to take a closer look with a full autism evaluation.

How Is Autism Diagnosed?

The diversity of autism spectrum disorder can make it difficult to correctly diagnose. Sometimes children with ASD are mistakenly diagnosed with a different disorder, like attention-deficit hyperactivity disorder (ADHD) oroppositional defiant disorder (ODD), or they are told that nothing is wrong. Other times kids are diagnosed with autism when they actually aren’t on the spectrum.

There are a variety of screeners that pediatricians or other practitioners might employ as a first step to learning if a child might have autism, before beginning a formal evaluation. Some are questionnaires that parents fill out and others are assessments done by clinicians. If a screener indicates that a child may have autism spectrum disorder, the child should receive a comprehensive evaluation with someone trained in diagnosing autism. This evaluation should include assessment of a child’s behaviors in different settings and within the context of their overall development, and it should incorporate both clinician observation and parent/caregiver interviews. Evaluations will often include autism-symptom specific measures such as:

• The Autism Diagnostic Observation Schedule, or the ADOS-2. This is a test with different modules to accommodate a range of children. The purpose of the ADOS is to evaluate the social skills and repetitive behaviors the child displays during the test.
• The Autism Diagnostic Interview-Revised, or the ADI-R. This is a parent interview that gathers information about both current and past behaviors related to autism.

Evaluations should also include information about other areas of a child’s functioning across contexts. Assessing a child’s cognitive, motor, language and adaptive functioning can provide information on the most appropriate treatments and the impact their symptoms are having on their overall functioning. This includes using measures like:

• The Vineland Adaptive Behavior Scales, Third Edition (VABS-3). This is a parent interview that provides information about a child’s day-to-day functioning in areas of communication, socialization and daily living skills.
• Differential Ability Scales, Second Edition (DAS-II) or Mullen Scales of Early Learning (MSEL). These can be used to evaluate cognitive, language and motor functioning.

Even with these tools it is important to be working with a mental health professional who has experience diagnosing people on the autism spectrum