Being diagnosed with autism spectrum disorder usually begins with noticing a pattern of early signs or “red flags.” For children, parents, caregivers, teachers, or doctors may notice missed milestones, developmental delays, trouble communicating, or unusual behaviors. Other people with autism may not receive a diagnosis until they are adults.

There is no single test to diagnose autism. Your healthcare provider will want to take a thorough medical history and use various screening tools and tests to arrive at a diagnosis.

Recognizing and diagnosing autism early can lead to better outcomes for children, as they can get support for their developmental needs and practice communication skills. But a diagnosis can be beneficial at any age.

When Is an Autism Diagnosis Made for Children?

Some children may show signs of autism within the first year or two of life. However, the average age of diagnosis in the United States is 5 years old. Lots of factors can affect how early a child is diagnosed. Kids from lower-income households tend to get diagnosed a little later than those from wealthier families. The age of diagnosis also varies in different states.

Teachers may recommend an evaluation for older kids and teens who show signs of autism. For adults, the path to diagnosis may be a bit more complicated.

What Are the Early Signs of Autism?

Potential signs of autism within the first year of life can include:

• Making little or no eye contact
• Not babbling or making other vocal sounds
• Showing little or no social smiling or engagement
• Using few or no gestures, such as pointing or waving
• Not responding to their name by 12 months

When Is Autism Diagnosed in Adults?

The Centers for Disease Control and Prevention (CDC) estimates 2.21 percent of adults have an autism diagnosis. It’s likely there are also many adults with autism who haven’t been diagnosed.

Many adults with autism use a coping strategy called masking. They attempt to hide their symptoms to fit in socially, which can complicate diagnosis.

There’s no single test to diagnose autism in adults. If some of the signs of autism sound familiar, you can ask your health care provider whether further testing may be helpful.

These signs can include:

• Having difficulty making eye contact
• Feeling socially awkward or unsure how to act in social situations
• Struggling to understand social cues, like body language or tone of voice

Criteria for Autism Spectrum Disorder

There’s no blood test or physical exam that can diagnose autism. Instead, trained healthcare providers use standards published in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR).

DSM-5-TR explains autism diagnosis criteria, which covers several areas. The first is persistent challenges with social communication and interaction across multiple settings. This might include:

• Difficulty understanding how other people feel and responding to their emotions
• Difficulty using or understanding body language, gestures, facial expressions, or eye contact when interacting with others
• Difficulty developing, maintaining, and understanding relationships

A person with these issues might have trouble holding a back-and-forth conversation, interpreting others’ body language, and making or keeping friends.

The second criterion is restricted, repetitive patterns of behavior, interests, or activities. This would include at least two of the following:

• Repeating the same movements, actions with objects, or words over and over
• Preferring things to stay the same, following strict routines, or doing the same actions in a specific way
• Having very strong or intense interests in certain topics or activities
• Being unusually sensitive or not very responsive to sights, sounds, smells, touch, or other sensations

To qualify for an autism diagnosis, these symptoms have to cause significant impairment in functioning and they can’t be explained by another health condition.

The DSM-5-TR gives specific examples of autistic traits. It also rates how severe autism is on the following scale:

• Level 1 — Requiring support
• Level 2 — Requiring substantial support
• Level 3 — Requiring very substantial support

Screenings and school evaluations may catch symptoms of autism spectrum disorder, but they can’t diagnose it. Only a doctor or specialist can diagnose autism.

Screening

Screening is often the first step toward diagnosis for children with autism spectrum disorder. Children are increasingly screened for symptoms of autism at 18-month and 24-month well-child visits with a pediatrician or family physician. Screenings do not provide a diagnosis but are designed to detect early symptoms.

Initial screening involves a questionnaire about developmental milestones that’s completed by the parent. If milestones are delayed or if the parent has concerns, the child may be referred to a specialist for more in-depth assessment.

School Evaluations

For school-age children with disabilities, some testing can happen at school. A school evaluation or educational determination may be requested by the parent or recommended by the teacher. This is usually the first step in obtaining special education services and an individualized education program.

The evaluation is made by a team of education professionals and focuses on rating the level of disability and determining what services will be needed. The evaluation doesn’t provide a diagnosis. An independent evaluation can be obtained if parents disagree with the results of their child’s school evaluation.

Exams and Testing for Autism

It’s important to choose a specialist experienced in diagnosing autism spectrum disorder. Typically, autism is diagnosed by doctors such as psychiatrists, psychologists, and neuropsychologists. For children, specialists might also include developmental pediatricians or child psychiatrists. Speech and language pathologists may also be involved in autism diagnosis.

Medical professionals use a combination of tools to make an autism diagnosis. They begin by taking a thorough medical, family, and developmental history. Since risk factors for autism include both genetic and environmental factors, an autism assessment may include questions about:

• Family history of genetic disorders, epilepsy, or developmental problems
• The mother’s health during pregnancy
• Exposure to toxins during pregnancy or infancy

A clear picture may emerge from the medical history to help the doctor assess risk factors that strengthen the suspicion of autism or rule out other conditions. The doctor will perform a physical exam and will likely ask questions about:

• Seizures
• Allergies
• Gastrointestinal problems such as frequent constipation or diarrhea
• Sleep habits
• Developmental milestones
• Behavior patterns
• Sensory challenges

Neuropsychological Testing

A neuropsychological assessment is another evaluation that helps diagnose autism. A “neuropsych eval” may consist of one appointment lasting between four and eight hours or it can be spread over multiple appointments.

During an evaluation for children, the neuropsychologist will observe the child’s behavior and provide the child with tasks that allow the doctor to assess cognitive functioning, verbal and nonverbal reasoning, usage of language and communication, and motor skills. Results of this testing can help parents and schools better understand how the child learns and how best to meet their educational needs.

Neuropsychological assessments for adults also involve cognitive tests, and an examination of social, emotional, and behavioral skills. These might include interviews, tasks, questionnaires, or puzzles, as well as screenings for depression or anxiety. Your healthcare team can share more about the process with you.

Other Tests

Blood or saliva tests may be ordered to check for genetic syndromes such as Rett, fragile X, Prader-Willi, or Angelman that are often associated with autism.

The doctor may order screening tests to determine whether there are any problems with hearing or vision. Hearing and vision impairments are sometimes mistaken for autism in children. If a child has both autism and sensory impairments, it can complicate the diagnosis.

How Much Does It Cost To Get Tested for Autism?

There are several free online tools and phone apps that parents and caregivers can use to track their children’s development. These free tools can be the first step to help observe signs and share information with a healthcare provider.

Since the American Academy of Pediatrics recommends that all infants and toddlers get screened for developmental delays during their regular well visits (starting at 9 months of age), basic screening at the doctor’s office should be included with the cost of these normal checkup appointments. This cost may vary depending on your health insurance plan.

Seeing additional specialists for further testing can come with more expenses. You can call your insurance carrier to find out the potential cost before making your child’s appointment. In addition, your state may have government programs available for small children with disabilities to be evaluated and receive free services. Ask your child’s pediatrician or a social worker about resources that can help.

The cost of an autism diagnosis for an adult can vary greatly depending on which specialists are seen, the extent of neuropsychological testing, and how much insurance coverage a person has. Talk with your healthcare provider to find out which diagnostic tools and tests are recommended, and contact your insurance company to see what your costs might be.

Depending on the individual person’s needs, the cost of living with autism can vary. Psychiatry appointments, speech and language services, and behavioral therapy can all be autism-related expenses. However, public schools may be able to help support children with disabilities and provide some of these services during school at no extra cost to families.

What Is the Prognosis for Autism?

Autism spectrum disorder is a lifelong condition for nearly all people. However, with early and tailored interventions, many people see meaningful improvements in communication, social engagement, and daily functioning.

Between 25 percent and 30 percent of children with autism are nonspeaking or speak minimally. High schoolers with autism are 3 percent more likely to drop out before graduating compared to their peers. In addition, 74 percent of high school students with autism earn a diploma, compared to 86 percent of students overall.

About 60 percent of people with autism are successfully employed after taking advantage of vocational rehabilitation services for job placement. Seeking these services in high school can help people with autism plan their future.

Autism isn’t usually something that kids “grow out of.” However, a 2023 study suggested that up to 37 percent of those diagnosed with autism spectrum disorder as toddlers may no longer meet the criteria for the diagnosis by the time they’re in grade school. There’s a higher chance of this happening when interventions are intense and begin early. Getting retested can help you stay up to date on your child’s current needs.

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On MyAutismTeam, people share their experiences with autism, get advice, and find support from others who understand.

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