How do health care providers diagnose autism?

Health care providers look for certain symptoms or groups of symptoms to diagnose autism spectrum disorder (ASD). If you have concerns about your child's development, talk to his or her health care provider right away. The provider then can examine the child and check for specific problems, such as autism.

Your child's health care provider will check for problems with your child's development at every well-baby and well-child visit, even if you don't report any of the signs of autism or other problems.1,2 In addition, the American Academy of Pediatrics recommends that health care providers administer an ASD-specific tool to assess development at the 18-month and 24-month visits regardless of whether the child has risk factors for ASD.3

During these developmental screenings, the health care provider may:

  • Ask you specific questions about your child's actions and behavior
  • Ask you to fill out a questionnaire about your child's behavior
  • Speak directly to the child

The health care provider might use a screening test specifically for ASD. This test might be the Checklist of Autism in Toddlers (CHAT), the Modified Checklist for Autism in Toddlers (M-CHAT), or another test.1

In addition, the health care provider may also recommend that your child have a blood test to help rule out some other conditions and problems.2

Depending on the results of the blood test and the developmental and other screenings, your child's health care provider will either:

  • Rule out autism or
  • Refer your child to a specialist in child development or another specialized field to diagnose the child with autism. The specialist will then do a number of tests to figure out whether your child has autism or another condition. These will include tests of your child's communication abilities and observation of the child's behaviors.

Because the diagnostic criteria for ASD changed in 2013 (see below), ongoing research will help ensure that these screening tests are accurately identifying children who meet the new criteria for ASD.

The American Psychiatric Association, a professional society of psychiatrists, updated the criteria for an autism diagnosis in May 2013. The criteria are published in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).

According to the DSM-5 criteria, a person has ASD if he or she:4

  • Has problems with communication and social interactions, namely:
    • Doesn't respond appropriately to social and emotional cues
    • Has deficits in nonverbal communication during social interactions
    • Has trouble developing friendships, keeping friends, and understanding relationships
  • Has at least two types of repetitive behavioral patterns. These might include repetitive movements, inflexible routines, very restricted interests, or unusual responses to certain sensory inputs, such as the way a particular object feels.

There are various tools that specialists commonly use to diagnose autism. The only tool that currently fits the revised DSM-5 criteria is the Autism Diagnostic Observation Schedule (ADOS-2). However, it alone is not enough to make a diagnosis of ASD. Existing diagnostic tools are being modified to better fit the DSM-5 criteria.

During an ADOS-2 assessment, the specialist interacts directly with your child in social and play activities. For example, the specialist will see whether your child responds to his or her name and how he or she performs in pretend play, such as with dolls. The specialist is looking for specific characteristics that are hallmarks of ASD. To be diagnosed with ASD, a child must have had symptoms since an early age.4

As part of the diagnosis, the specialist will also note whether your child has:4

  • Any genetic disorder that is known to cause ASD or its symptoms, including Fragile X syndrome or Rett syndrome; your child might receive a genetic test to detect these types of disorders.
  • A language disability and the level of disability
  • Intellectual disability and the level of disability
  • Any medical conditions common among those with ASD, such as seizures, anxiety, depression, or problems with the digestive system

Depending on your child's unique symptoms and needs, the team of specialists may also want to give your child a range of other tests. If your child shows symptoms of seizures, a brain specialist, or neurologist, might use electrical sensors to observe your child's brain activity.

Your child may need other tests to determine how best to treat the symptoms of ASD. A hearing specialist, or audiologist, might test your child's hearing, which can sometimes seem poor in children with ASD. Other tests might include tests of muscle strength and tests of your child's ability to control movement.


  1. Myers, S. M., & Johnson, C. P.; American Academy of Pediatrics Council on Children with Disabilities. (2007). Management of children with autism spectrum disorders. Pediatrics, 120(5), 1162–1182.
  2. Johnson, C. P., & Myers, S. M.; American Academy of Pediatrics Council on Children with Disabilities. (2007). Identification and evaluation of children with autism spectrum disorders. Pediatrics, 120(5), 1183–1215.
  3. American Academy of Pediatrics. (2006). Identifying infants and young children with developmental disorders in the medical home: An algorithm for developmental screening and surveillance. Pediatrics, 118(1), 405–420.
  4. Diagnostic and Statistical Manual of Mental Disorders, 5th edition. (2013). American Psychiatric Association: Washington, DC.
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