How Autism is Diagnosed and What to Expect

Autism is diagnosed through a comprehensive evaluation, not a single test. There is no blood test or brain scan that diagnoses autism. Instead, a qualified specialist assesses your child's developmental history, observes their behavior directly, and uses standardized tools to build a complete picture. The process typically involves multiple steps and can take several hours, sometimes spread across more than one appointment.

An upcoming autism assessment can raise many questions, especially if it’s your first one. Autism, also known as autism spectrum disorder (ASD), is assessed through a combination of observation, developmental history, and standardized tests. Together, these offer information about your child’s social, communicative, and behavioral patterns. Physicians, nurse practitioners, psychologists, and other healthcare professionals who specialize in child development conduct these assessments.  

What is autism? 

Autism refers to a unique trajectory of brain development that affects how a person perceives the world, interacts with others, and processes information. Signs and behaviors can vary significantly from one person to another, but common indicators include unique features of social interaction and communication, as well as patterns of thoughts, behaviors, and sensory responses to the environment that might be less flexible. Early diagnosis and intervention can significantly improve the quality of life for autistic people and their families. 

How is autism diagnosed? 

The diagnostic process for autism typically begins with the evaluation of specific criteria outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). These criteria focus on social communication and interaction, as well as repetitive and restrictive patterns of behavior. 

A comprehensive evaluation is crucial for an accurate diagnosis, as it considers various aspects of a child's development, behavior, and functioning. This evaluation often includes medical, developmental, and behavioral assessments. 

Who can provide an autism diagnosis? 

 Various professionals can diagnose autism, including: 

• Neurologists  

• Pediatricians 

• Developmental and behavioral pediatricians 

• Child psychiatrists 

• Child psychologists 

• Neuropsychologists

How to prepare for an autism assessment 

As a caregiver preparing for your child's autism assessment, it’s helpful to gather all relevant medical records, documentation of developmental milestones, and any educational or behavioral reports that may offer valuable insights into your child's history. On the day of the evaluation, take steps to help your child feel well-rested and comfortable, as their emotional state can impact the assessment's accuracy. Lastly, remember that open communication with the assessment team is vital. Sharing your observations and experiences as a caregiver can help create a comprehensive understanding of your child's unique strengths and challenges.  

A look at autism diagnostic tests 

Several tests can aid in diagnosing autism, including: 

• Autism Diagnostic Observation Schedule (ADOS): This standardized assessment involves a professional observing and interacting with your child. The assessment looks at social communication, social interaction, and other behaviors, usually taking about 40 minutes. Results are typically available within a few weeks. 

• Autism Diagnostic Interview-Revised (ADI-R): This structured interview is conducted with the child's caregiver and assesses the child's developmental history, social interactions, communication skills, and other behaviors. It takes about 90 minutes to complete, with results available within a few weeks. 

• Childhood Autism Rating Scale (CARS): The CARS is a 15-item rating scale that evaluates social interaction, communication, and other behaviors. It takes about 30 minutes to complete, and results are typically available within a few weeks. 

• Vineland Adaptive Behavior Scales, Third Edition (Vineland-3): The Vineland-3 is an assessment tool that measures adaptive behavior, which includes communication, daily living skills, socialization, and motor skills. It’s often used in conjunction with other autism diagnostic tests to provide a comprehensive understanding of a child's development. The test is administered through a semi-structured interview with the child's caregiver, usually taking about 60 to 90 minutes to complete. Results are typically available within a few weeks. 

Additional tests are often helpful, depending on your child's needs, such as speech and language assessments, cognitive tests, and medical evaluations. 

What to anticipate during a diagnostic evaluation

During the diagnostic evaluation, expect the clinician to ask questions about your child's developmental history, social interactions, and behavior. They may also observe and assess your child's behavior in various settings. Medical evaluation is important for all children who receive an autism diagnosis. 

How long does an autism evaluation take?

A single evaluation appointment typically takes two to four hours, depending on the tools used and your child's age and needs. Some evaluations are spread across multiple appointments. Results and a written report are usually shared within two to four weeks of the completed assessment.

Wait times for an initial evaluation appointment vary significantly depending on where you live, sometimes ranging from a few weeks to several months. If you are concerned about wait times, ask your pediatrician about early intervention programs, which can often begin supporting a young child before a formal diagnosis is complete.

Next steps after receiving a diagnosis 

After a diagnosis is made, the clinician may refer your family to appropriate services or develop a treatment plan tailored to the child's needs. Recommended therapies and services might include behavior therapy such as applied behavior analysis (ABA), or developmental therapies including speech therapy, occupational therapy, physical therapy, or music therapy. A clinician might also recommend counseling for certain family members.  

It is essential to receive an accurate diagnosis to ensure the most effective support and intervention for your child. If you have doubts or concerns, consider seeking a second opinion. Remember, the road to understanding and supporting a loved one with autism is a journey, and having accurate information and compassionate care makes a world of difference.