By Raising Children Network
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Grown-up holding toddler with abacus credit iStockphoto/jo unruh

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  • Research shows that when parents have concerns about their child’s development, they’re usually correct.
  • If you’re worried, don’t wait - speak to your GP or maternal child health nurse about your concerns.
There is no single test for diagnosing autism spectrum disorder (ASD). Diagnosis ASD usually involves a range of tests and measures. Often, it also involves several different specialists and professionals. Although this might seem scary, a combination of tests and professionals can achieve an accurate diagnosis and appropriate treatment plan.

How autism spectrum disorder is diagnosed

There is no single test available to diagnose autism spectrum disorder (ASD). Instead, diagnosis is based on watching how a child plays and interacts with others (current development), interviewing parents, and reviewing the child’s developmental history (past development).

By using a combination of tools, professionals can diagnose a child with ASD, and determine where on the spectrum the child falls.

When diagnosing ASD, professionals like psychiatrists and psychologists will refer to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). This tool breaks down the signs and symptoms of ASD into categories. It also states how many of these must be present in each category to confirm a diagnosis of ASD in children.

You can read the DSM-5 criteria for a diagnosis of ASD.

Most people find the diagnosis process quite confronting. It’s not much fun having someone point out all the things that your child can’t do – things that typical children just pick up naturally. But think of this assessment as a benchmark, against which you can measure your child’s progress once they start in an intervention program.
– Seana Smith, mother of four and co-author, Australian Autism Handbook

Professionals who can diagnose autism spectrum disorder

A paediatrician, psychiatrist, psychologist or other professional trained in autism spectrum disorder (ASD) can diagnose a child with ASD. If your child receives a diagnosis of ASD, she might be eligible for financial support from the government and access to early intervention. If so, your child will need to be seen by a combination of these professionals.

You might need a referral to see these professionals, so your GP or maternal and child health nurse are great places to start. Visit our Autism Services Pathfinder to find out more about the steps to diagnosis. 

The professional looking after your child will probably request a multidisciplinary assessment of your child. This means that the professional will consult with specialists from other fields to ensure that the diagnosis is accurate, and to develop the best treatment plan.

Second opinions
You know your child best. If you have genuine concerns about your child’s development, seek further help. If your paediatrician doesn’t have any concerns about your child, but you’re still worried, get a second opinion.

Talking to other parents can be a great way to find the right doctor. Visit our forum for parents of children with ASD to connect with other parents.

Video Getting the diagnosis – what and how

This short video features parent stories about children's autism spectrum disorder (ASD) diagnoses. Parents share their experiences of the process, from spotting first warning signs to getting a diagnosis. They note that getting a diagnosis is not always quick or easy, but it's important to persevere.


Tests and tools for diagnosing autism spectrum disorder

Although no test or tool can replace diagnosis by an experienced clinician, there are standardised tools that help clinicians with diagnosing autism spectrum disorder (ASD).

Some of the tests and screening measures that can assist in the diagnosis of ASD include:

  • Autism Diagnostic Observation Schedule (ADOS)
  • Autism Diagnostic Interview (ADI)
  • the Childhood Autism Rating Scales (CARS)
  • Modified Checklist for Autism in Toddlers (M-CHAT)
  • Developmental Behaviour Checklist (DBC)
  • Social Communication Questionnaire (SCQ)
  • Psycho Educational Profile - Revised (PEP-R)
  • Autism Behaviour Checklist (ABC).

These tools might not identify every child on the spectrum, especially those who have only milder signs of ASD. 

Testing for other medical difficulties and delays

Because other medical difficulties sometimes go along with autism spectrum disorder (ASD), your paediatrician might also do other tests, such as a physical examination and history, and a hearing test. These tests:

  • check for signs of other conditions that might explain your child’s symptoms
  • help to identify any other medical problems that might require treatment.

The child should also receive a cognitive assessment (IQ test), which can identify developmental strengths and weaknesses. The assessment will also identify whether your child has an intellectual disability, common in many (but not all) children with ASD.

Most children will also have a language assessment by a speech pathologist.

Waiting for a diagnosis of autism spectrum disorder

You might find you’re put on a waiting list for assessment. The important thing is not to see this as a period when nothing happens. If you can, look for options – you might be able to get an assessment sooner. The Autism Services Pathfinder can show you all the options for diagnosis. There are also services that will allow you to start programs and therapies without a diagnosis. 

Occasionally, the outcome of your assessment might be a recommended period of ‘watchful waiting’. This means your health care practitioner wants to wait to see whether your child’s symptoms change with a few more months of development. It’s possible the symptoms might resolve or become more pronounced.

If you’re told to wait and watch, again the key is to be proactive:

  • Get your child checked every three months.
  • Seek a second opinion if you feel you want one.
  • Start exploring early intervention options in your area.

For more information on ASD and early intervention options, you could attend a free Early Days workshop in your area. Another option is contacting your state autism association.

Video Reactions to an ASD diagnosis

If your child is diagnosed with autism spectrum disorder (ASD), you might go through many feelings and reactions.

As the parents in this video explain, reactions to an ASD diagnosis can include relief, sadness, shock, denial and anger. Everybody’s different, and there’s no one right way to feel. But these parents do say that it’s important to work through your emotions. This way you can start to help your child.

  • Last updated or reviewed 20-11-2013
  • Acknowledgements This article was developed in collaboration with Cheryl Dissanayake and Cherie Green, Olga Tennison Autism Research Centre, La Trobe University.