• Posted February 28, 2024

How Is Autism Diagnosed?

According to the advocacy group Autism Speaks, one in every 36 U.S. children has an autism spectrum disorder (ASD).

Early diagnosis is crucial to helping to treat the condition, but how is a diagnosis done?

The U.S. Centers for Disease Control and Prevention has an updated review of what's involved in diagnosing autism in kids.

"Diagnosing autism spectrum disorder [ASD] can be difficult because there is no medical test, like a blood test, to diagnose the disorder," the agency noted. "Doctors look at the child's developmental history and behavior to make a diagnosis."

At what age can a diagnosis be made?

According to the CDC, the time at which a child receives a diagnosis varies. Sometimes an ASD can be detected as young as 18 months, or even before, but only by the age of 2 can a diagnosis by a trained professional be considered reliable.

Unfortunately, in many cases a diagnosis of autism may not come till later in childhood. Some people are unaware that they have an ASD until they are diagnosed as an adult.

Ideally, a reliable diagnosis should take place in childhood, when therapies are most effective, the CDC said.

Monitoring development

As children grow, conversations between parents and health care providers that center on kids' skills and abilities should be encouraged, the CDC said.

Tracking your child's development -- how soon they reach typical developmental milestones, for example -- is key. These age-linked milestones include skills observed in playing, learning, speaking, behaving and moving.

Everyone can be part of the "developmental monitoring" process -- parents, grandparents, daycare workers and teachers, can all give feedback on how a child is progressing.

The CDC has links to pages that can help -- Learn the Signs, Act Early, which includes guidance on developmental milestones.

"If you notice that your child is not meeting milestones, talk with your doctor or nurse about your concerns and ask about developmental screening," the CDC advises.

Well-child visits to pediatricians, family doctors and nurses may also include routine developmental monitoring, including questions as to whether your child is meeting milestones.

Be sure to also inform providers about any family history of autism, learning disorders, intellectual disability or attention deficit-hyperactivity disorder (ADHD).

Screening for developmental issues and autism

The American Academy of Pediatrics advises that developmental and behavioral screening occur for all children during regular well-child visits at these ages:

• 9 months

• 18 months

• 30 months

When it comes to ASD screening specifically, those should occur at 18 months and 2 years of age, according to AAP recommendations.

Screening can also happen at other times, should a caregiver or a doctor be concerned that a child might have autism, or if a child is at high risk for an ASD (for example, the child has a sibling or other family member with ASD).

Don't wait for the provider to offer a developmental screening test for your child. If one is not not conducted at the recommended ages, "you can ask that it be done," the CDC said.

In a typical ASD screening, parents will be asked questions about "language, movement and thinking skills, as a well as behaviors and emotions," the CDC said.

Brief developmental screenings do not provide a diagnosis of an ASD, but they could point out that a proper autism screening is needed.

That screening "is a more in-depth look at a child's development and is usually done by a trained specialist such as a developmental pediatrician, child psychologist, speech-language pathologist, occupational therapist or other specialist," the CDC said.

At that point, a specialist may give the child a structured test, and ask more questions of parents and caregivers.

"A diagnosis of ASD now includes several conditions that used to be diagnosed separately; autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), and Asperger syndrome," the CDC noted. "Your doctor or other healthcare provider can help you understand and navigate the diagnostic process."

What next?

A formal evaluation of your child might indicate that early therapeutic interventions for an ASD might be necessary. As well,  the specialist might recommend genetic counseling and testing for your child, the CDC said.

SOURCE: U.S. Centers for Disease Control and Prevention