Autism Diagnostic Process

 

Developmental Monitoring

Developmental monitoring is an active, ongoing process of watching a child grow and encouraging conversations between parents and providers about a child's skills and abilities. Developmental monitoring involves observing how your child grows and whether your child meets the typical developmental milestones, or skills that most children reach by a certain age, in playing, learning, speaking, behaving, and moving.

When you take your child to a well visit, your child's doctor or nurse will also do developmental monitoring. The doctor or nurse might ask questions about your child's development or will talk and play with your child to see if they are developing and meeting milestones. (CDC, 2025).

Developmental Screening

Developmental screening takes a closer look at how your child is developing and is more formal than developmental monitoring. It is a regular part of some well-child visits even if there is not a known concern.

The American Academy of Pediatrics (AAP) recommends developmental and behavioral screening for all children during regular well-child visits starting at the age of 9 months.

In addition, AAP recommends that all children be screened specifically for autism during regular well-child visits at 18 months and again at 24 months.

Developmental screening can be done by a doctor or nurse, or other professionals in healthcare, community, or school settings. Your doctor may ask you to complete a questionnaire as part of the screening process. Additional screening should also be done if a child is at high risk due to a family history of autism, or if behaviors associated with autism are present.

If your child’s healthcare provider does not periodically check your child with a developmental screening tool, you can ask that it be done.

The Modified Checklist of Autism in Toddlers (M-CHAT-R) is one of the AAP’s recommended tools. The M-CHAT-R™ is a scientifically validated checklist of questions used for screening children between 16 and 30 months of age to assess their risk for autism spectrum disorder (ASD). The MCHAT-R screener should be completed by the family and a professional to screen for red flags associated with autism. The MCHAT screener does not diagnose, it is only used to identify children who may need to be referred for a full evaluation. There is a possibility that your child may fail the M-CHAT-R but may not meet criteria for a diagnosis of autism. Therefore, it is important to follow up with your health care provider (Hyman, 2020).

Other Recommended Evaluations

A screening tool does not provide a diagnosis, but it indicates if a child is on the right development track or if a specialist should take a closer look. Your health care provider may provide referrals for additional testing or refer your child for Early Intervention services prior to an autism evaluation.  

- An audiological assessment (hearing test) referral should be made for all concerns regarding speech, language or hearing difficulties. This is usually done by an audiologist.

- A cognitive evaluation (or developmental assessment) using standardized tests that measure both verbal and nonverbal abilities should be performed by a professional experienced in testing children.

- A medical and neurological evaluation may need to be conducted to assess such issues as acquired brain injury, seizure disorder, self-injury and sleep or eating disturbances.

- A speech-language-communication evaluation should be performed on all children who have communication difficulties. This is typically done by a speech-language pathologist (SLP).

- A physical or occupational therapist should assess a child's sensorimotor skills if they exhibit difficulties with movement or sensory responses.

Comprehensive Evaluation of Autism Spectrum Disorder

If the screening tool identifies an area of concern, a formal evaluation may be needed. This formal evaluation is an in-depth look at a child’s behavioral development. These assessments are usually conducted by a team of specialists, including neurodevelopmental pediatrician, psychologist, or psychiatrist. General pediatricians and child psychologists comfortable with application of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria can also make an initial clinical diagnosis. The specialist may observe the child, give the child structured tasks, ask the parents or caregivers questions, or ask them to fill out questionnaires. The results of these formal evaluations highlight your child's strengths and challenges and can inform whether they meet criteria for a developmental diagnosis of autism. Having a clinical diagnosis facilitates initiation of behavioral and/or adaptive services. Currently, there are no medical tests (blood tests, scans, or X-rays) to diagnose autism. It is based on behavioral testing; therefore, careful review of the child’s behavioral history and direct observation of symptoms are necessary.

Comprehensive Documentation

Upon a clinical diagnosis of autism, the diagnosing specialist should provide a comprehensive written report of the results of your child’s evaluation. This should also include information on your child’s present developmental levels of functioning. For Nevada Medicaid purposes, the diagnostic comprehensive report should also be accompanied by a form called Autism Spectrum Disorder (ASD) Diagnosis Certification for Requesting Initial Applied Behavior Analysis (ABA) Services (also known as the FA-11F form). This form is needed for prior authorization of intervention and treatment of autism.

 

Document Resources:

Centers for Disease Control. (2025, April 15). Screening for Autism Spectrum Disorder. Centers for Disease Control and Prevention.  https://www.cdc.gov/autism/diagnosis/index.html.

 

Hyman, S. L., Levy, S. E., Myers, S. M., & Council On Children With Disabilities, S. O. D. A. B. P. (2020, January 1). Identification, evaluation, and management of children with autism spectrum disorder. American Academy of Pediatrics. https://publications.aap.org/pediatrics/article/145/1/e20193447/36917/Identification-Evaluation-and-Management-of?autologincheck=redirected.