How Is Autism Diagnosed? Screening, Testing and Diagnosis

April 23, 2021

Looking for an autism diagnosis? ABA Centers of America now offers thorough autism screening, autism testing, and autism diagnosis.


If you’ve noticed that your child has been having trouble adapting to social situations or their communication skills are not the same as those of other children, you might wonder if your child has autism. Because autism can be experienced differently by different people, it can be difficult for you to know what’s going on. For this reason, you might be asking yourself: “How is autism diagnosed?”

Maybe you’ve done a bit of online research, but you still aren’t sure about how you can help your child. It can be confusing because there are so many different steps involved, such as autism screening, testing, and diagnosis.

Autism Early Signs

There are different early signs of autism that can help you determine whether you need to take the next steps toward autism testing, screening, and diagnosis. These signs that may be exhibited in your child’s behavior include:

  • Not smiling when expected
  • Not responding when you say their name
  • Preferring to play alone
  • Not looking at objects when you point them out
  • Not responding to facial expressions

Additionally, you may find that your child is highly sensitive to certain light, textures, scents, and sounds. They might have a good memory for songs, letters, or numbers. If they have challenges socializing with other children their age, this is another potential sign of autism.

How Is Autism Diagnosed?

Because there isn’t a specific medical test for autism (for example, a blood test), it can be difficult to diagnose. However, there are steps you can take, after which a qualified doctor can provide you with an autism diagnosis.

Developmental Monitoring

If you’ve noticed any of the early signs of autism above, the next step is to engage in developmental monitoring. You can do this yourself, along with the help of other caregivers in your family. When you engage in development monitoring, you’re paying attention to your child’s growth and change as time passes.

You’ll need to see whether your child develops according to milestones related to moving, behaving, speaking, learning, and playing. To get an idea of what these milestones might look like, the CDC has a comprehensive page on developmental milestones with several free tools you can use.

If you and other caretakers find that your child isn’t developing according to these milestones, you might want to speak with your family doctor or pediatrician. You can also ask your child’s health provider to do regular autism developmental monitoring checks. They will ask you questions about your child’s behavior when they do this and play and talk with your child, too.

If it seems like your child might have autism based on developmental monitoring, then you’ll move onto developmental screening.

Developmental Screening for Autism

Usually, a nurse, doctor, or another professional in school, community, or a healthcare setting will do a developmental screening. This is a formal process and is usually only used if there’s a concern after you’ve identified some challenges during developmental monitoring.

For all children, it’s recommended that they be tested for developmental screening at 9, 18, and 30 months. There are studies that show one in four children under the age of 6 is at risk for a developmental delay or disability. So whether or not you suspect your child has autism, you should be doing these tests. If you think your child might have autism, then these tests should also be done at 24 months and at other times if challenges continue.

In a developmental screening, you will be asked to fill out a questionnaire about your child, or your child may take a short test. These tests will be used to focus on specific elements of your child’s development. These elements include:

  • Emotions
  • Behavior
  • Thinking
  • Movement
  • Language

There are also some factors, such as lead exposure, low birth weight, and preterm birth, that may mean your child is more likely to have autism. In these cases, you should bring your child in more often for developmental screening.

If your child’s healthcare provider doesn’t offer these types of tests, you can ask that they do so.

Developmental Screening Questionnaires for Autism

There are four tests that are most often used during developmental screening:

  1. The Ages and Stages Questionnaires SE-2, which you will fill out. It includes questions about problem-solving, fine motor skills, gross motor skills, and communication.
  2. The Communication and Symbolic Behavior Scales test, where you will fill out a checklist when your child is aged 6 to 24 months.
  3. The Parents’ Evaluation of Developmental Status, in which you’ll answer 10 questions about your child.
  4. The Modified Checklist for Autism in Toddlers. Here, you’ll answer 20 questions.

If you want help understanding the results of any of these tests, you can speak with your child’s doctor. Depending on the answers, it may be time for you to move to the next step.

Autism Testing

Usually, the person who completes this testing is a specialist such as a developmental pediatrician or child psychologist. Note that there isn’t one specific autism evaluation test. Instead, these experts will have to use a range of tests that are autism-specific. If you’re wondering how doctors diagnose autism, it begins with these tests.

The Tests

  1. The Autism Diagnostic Observation Schedule. When an expert uses this test, they will observe your child’s repetitive behavior, play, communication, and social skills. Tests vary depending on your child’s age.
  2. Autism Diagnostic Interview-Revised test. During this test, the specialist will speak with you about your child’s past and current behaviors related to autism.
  3. The Childhood Autism Rating Scale, Second Edition. This is a test made of 15 questions, which will help the specialist determine whether your child has another condition that is not autism. This is an important test, as some children might have a condition that’s easily confused with autism (such as ADHD). They might also have a combination of conditions.

Additional Evaluations

In addition to using the diagnostic tests above, a specialist might test your child on their cognition, motor skills, language, vision, and hearing. It may take a bit of time before you are able to get an autism diagnosis, but with a combination of evaluations, you’ll get there.

Getting an Autism Diagnosis

Once you have undergone all these screenings and tests, a qualified professional (child psychologist, child psychiatrist, pediatric neurologist, or developmental pediatrician) will be able to make a diagnosis. Usually, these child professionals use the American Psychiatric Association’s Diagnostic and Statistical Manual, along with test results, to make the diagnosis.

To be sure that this diagnosis is correct, you need to ensure that the specialist knows your child’s behavior well. Ideally, your child will have gone through rigorous testing with them over time so that they know how your child has developed.

When you receive an autism diagnosis from a specialist, this an official medical diagnosis. Note that the medical diagnosis of autism is different from an educational determination, which happens when a group of school professionals decides whether or not a child should be enrolled in special education.

Autism Treatment with ABA Therapy

Once you have this diagnosis in the form of a diagnostic report, you can begin to explore proper therapy, schooling and care for your child. Be sure to check out our Resources page for links to various government agencies and support organizations. If you’re in need of autism testing or an autism diagnosis, check out our autism diagnosis services.

At ABA Centers of America, we specialize in helping families create the brightest future possible. We are here to help children grow, learn, and lead fulfilling lives. Our therapists are licensed and board-certified. We have experience with all forms of autism across the spectrum and with people of all ages.

To learn more about how we can help you, call us for a free consultation with one of our autism treatment professionals.