Screening & diagnosis.

Identifying Autism.


When family members or support providers become concerned that a child is not following a typical developmental course, they turn to experts, including psychologists, educators and medical professionals, for a diagnosis.

At first glance, some people with Autism may appear to have an intellectual disability, sensory processing issues, or problems with hearing or vision, and the diagnosis of Autism may become more challenging.

These conditions can co-occur with Autism and it can be confusing to families when they receive multiple diagnoses. However, it is important to identify Autism, as an accurate and early Autism diagnosis can provide the basis for appropriate educational and home-based support.

There are many differences between a medical diagnosis and an educational determination, or school evaluation, of a disability.

Understanding Autism
A medical diagnosis is made by a psychologist, developmental pediatrician, or other specialized physician based on an assessment of symptoms and diagnostic tests. A medical diagnosis of Autism spectrum disorder is most frequently made according to the Diagnostic and Statistical Manual (DSM-5, released 2013) of the American Psychiatric Association. This manual guides physicians in diagnosing Autism spectrum disorder according to a specific set of criterion.
A brief observation in a single setting cannot present a true picture of someone’s abilities and behaviors. The person’s developmental history and input from parents, caregivers and/or teachers are important components of an accurate diagnosis.

An educational determination is made by a multidisciplinary evaluation team of various school professionals. The evaluation results are reviewed by a team of qualified professionals and the parents to determine whether a student qualifies for special education and related services under the Individuals with Disabilities Education Act (IDEA) (Hawkins, 2009).

An educational determination can qualify an individual for support within school settings. However, an educational determination is not the same as a medical diagnosis, and often will not qualify an individual for therapies and support outside of school that would typically be covered by insurance or Medicaid. Additionally, a medical diagnosis of Autism does not guarantee an educational determination.

Early identification is associated with dramatically better outcomes for Autistic people. The earlier a child is diagnosed, the earlier they can begin benefiting from early intervention therapies and education.

The Centers for Disease Control and Prevention’s National Center on Birth Defects and Developmental Disabilities (NCBDD) recommends that all children be screened for Autism by their family pediatrician three times by the age of three – at nine, 18, and 24 or 30 months. Intervention should start when an Autism diagnosis is suspected, rather than when a formal diagnosis is made.

The advantages of early intervention cannot be overemphasized. Children who receive early intervention can make tremendous strides in their overall skill development, leading to improved quality of life.

The CDC provides a wealth of information on the early signs of Autism through its “Learn the Signs. Act Early” initiative.

While there is no one behavioral or communication assessment that can detect Autism, several screening instruments have been developed for use in determining if a child might need further evaluation for developmental delay and/or Autism, including the Ages and Stages Questionnaire (ASQ) and the Modified Checklist for Autism in Toddlers (M-CHAT). For detailed information about these instruments and the research behind them, click here.

Medical diagnosis.

Medical professionals who may have experience with Autism and other neurodevelopmental disorders include pediatricians (especially developmental pediatricians), neurologists, psychiatrists and psychologists. Not every one of these professionals has experience with Autism, so you should seek recommendations of knowledgeable professionals in your area from:

  • Our information and referral service
  • Autism support groups
  • People who have children or other family members with Autism
  • Your primary care provider

A skilled practitioner can begin the assessment; the evaluation itself can vary depending on the professional administering it, the age of the person being assessed, the severity of his or her needs, and local available resources. A medical assessment for Autism typically includes:

  • A medical history of the mother’s pregnancy
  • Developmental milestones
  • Sensory challenges
  • Medical illnesses, including ear infections and seizures
  • Any family history of developmental disorders
  • Any family history of genetic and metabolic disorders
  • An assessment of cognitive functioning
  • An assessment of language skills
  • An Autism-specific observational test, interview or rating scale


There are no medical tests, such as blood work or brain scans, for diagnosing Autism. An accurate medical diagnosis must be based on observation of the individual’s communication, social interaction, and their activities and interests.

Contact our Information and Referral team for information on where to get a diagnosis in South Carolina or click here.

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While there is not a single behavioral or communication test that can detect Autism, several Autism-specific tools are now being used for formal diagnosis. These include the Autism Diagnostic Observation Schedule, Second Edition (ADOS™-2), the Autism Diagnostic Interview (ADI), the Screening Tool for Autism in Toddlers (STAT), the Childhood Autism Rating Scales (CARS), and the Tele-ASD-Peds for diagnosis for use in telehealth. All of these tests should be used as part of a larger assessment, and not just on their own, as the determination of Autism is best completed with multiple sources of information.

Related and co-occuring conditions.

Immune and GI systems.

Increasing evidence shows that gastrointestinal (GI) symptoms, such as gastrointestinal disruption, abdominal pain, diarrhea, constipation, and flatulence, has been characterized as a common comorbidity in patients with ASD, ranging between 9 and 84% depending on the studies being retrospective or prospective (Wasilewska and Klukowski, 2015), and are linked to the severity of ASD symptoms (Adams et al., 2011; Gorrindo et al., 2012; Chaidez et al., 2014).

According to an article published by Frontiers in Neuroscience, scientists widely accept the gut-brain axis theory, which states that the gut and the brain communicate and influence each other (Bienenstock et al., 2015; Mayer et al., 2015; Cryan et al., 2019).

Despite this connection, there has yet to be a proven cause-effect relationship between Autism and GI symptoms. The brain-belly connection of gut microbiota remains an area of research for those concerned with both GI and immune connections to neurological differences and disorders.

IQ concerns.

Research studies have frequently used inappropriate IQ tests, such as verbal tests with nonverbal individuals, and in some cases have estimated intelligence level without any objective evidence. Tests that do not require language skills, such as the Test of Nonverbal Intelligence (TONI), can offer more accurate information about the person.

Chronic Constipation and/or Diarrhea

Medical literature states that about 47 percent of Autistic adults and 45 percent of Autistic children have gastrointestinal symptoms. Diarrhea is most common, followed by abdominal pain and constipation. Constipation in Autistic people is usually not hard, impacted stools, but the slow passage of stools with long gaps in between, and loose stools when they do come.

Low muscle tone.

About 30 percent of children with Autism have moderate to severe loss of muscle tone, which can limit their gross and fine motor skills.


Some people with Autism have very high pain thresholds (insensitivity to pain), while others have very low pain thresholds. There are interventions, such as sensory integration therapy, designed to help increase reliability of their sensory processing and integration.


About 30 percent of children with Autism have moderate to severe pica, a compulsive eating-disorder characterized by eating non-food items such as paint, sand, dirt, paper, etc. Pica can be dangerous as ingesting these inedible substances can cause choking, digestive problems, parasitic infections, and other illnesses.


It is estimated that around 30 percent of people with Autism develop epilepsy, some in early childhood and others as they go through hormone level changes in puberty. Suspected seizures should be confirmed by electroencephalogram (EEG) and treated with prescribed anticonvulsant medications.

Sensory problems.

The diagnosis of Autism includes atypical responses to sounds, sights, touch, taste and smells. High-pitched intermittent sounds, such as fire alarms or school bells, may be painful for people with Autism. Scratchy fabrics and clothing tags may also be intolerable, and some people have visual sensitivities, such as the flickering of fluorescent lights.

These are only a few examples of sensory experiences. Sensory needs can range in severity and change over time. Consult an occupational therapist for support in evaluating and supporting sensory processing and integration.

Sleep problems.

Many people who experience Autism have sleep challenges. Night waking may be due to gastrointestinal issues, allergies, environmental intolerances, seizures or the effects of medications. Other potential causes are sleep apnea (pauses in breathing when the airway becomes obstructed during sleep), sleep terrors or confusional arousals. Individuals with sensory processing difficulties may have more problems falling asleep and increased periods of night waking.tween Autism and GI symptoms. The brain-belly connection of gut microbiota remains an area of research for those concerned with both GI and immune connections to neurological differences and disorders.

Hearing & visual impairment.

Children with a dual diagnosis of Autism and a sensory impairment face many possible paths. If the child is born deaf/hard of hearing or blind/visually impaired, that diagnosis is usually made early on, and Autism behaviors may be mistaken for a reaction to the sensory loss. Conversely, if a child with Autism has progressive hearing and visual impairments, his or her adaptation to the sensory loss may be misunderstood as a behavior of Autism. For more information, visit the Nebraska Center for the Education of Children who are Blind or Visually Impaired or this article about Autism and deafness. About 30 percent of children receiving education related to deafness/hard of hearing and blindness/visual impairment are also identified as having Autism. Every child should be able to enter his/her education program in the best aural and visual health possible, and should be monitored and tested to ensure continued health and care. For more in-depth information on hearing and vision screenings for people with Autism, see this article from the Autism Advocate. Families can feel overwhelmed and isolated while searching for information. The Autism Society offers a connection to the resources and support families need.

Connect with us.

Reach out to us here at the South Carolina Autism Society for information and resources.

Diagnosis per life stage.

Evaluations typically begin with your primary care provider and vary based on age. If your primary care professional does not wish to refer you to a diagnostician, or does not acknowledge your concerns, it is important to know that you have the right to contact a diagnostician for a second opinion.  Contact our Information and Referral team for information on where to get a diagnosis in South Carolina or click here.


Infant and toddler diagnosis begins with voicing your concerns with your child’s pediatrician or primary care doctor. A primary care professional should be able to review your child’s development and conduct a short Autism screening. If that screening indicates that Autism might be a possibility, the doctor may diagnose your child if they have training, especially if Autism characteristics are clearly present. If they do not have Autism-specific training, or if your child’s presentation is subtle or complicated by other factors, they may refer you to an Autism specialist.

Most Autism diagnosticians will not diagnose a child until they are at least one-year-old. However, if your child has delays, you can seek services before that diagnosis, often from early intervention federal programs, or from private speech, occupational therapy, or physical therapy clinics. Your primary care professional can give a referral to early intervention or private therapists.

Once your child is at least one-year-old, an Autism diagnostician (developmental pediatrician, child psychologist, child psychiatrist) can begin to explore evaluating them. The evaluation will consist of interviews with you, review of records, and an observation of or interaction with your child. See the section on Medical Diagnosis for more information.

Diagnosis for older children can follow a similar process to infants and toddlers. Contact your primary care professional for information about seeking an Autism evaluation. See the section on Medical Diagnosis for more information.

Another important area to consider for school-age children is seeking an evaluation within the school system. This process is separate from a medical diagnosis. A school evaluation can provide you and your child with federally mandated support in the school setting, via the special education system. Your child can have both a medical diagnosis of Autism and a school determination of Autism to get support in all the settings possible, including home, community, and school.

Some professionals recommend getting the medical diagnosis first, as its support will go into effect before a child enters school, and will often expedite the school determination process. However, the medical diagnosis and the school determination can be done in the order that best meets the needs of your child and your family.
The first step in obtaining special education services for a school-age child is for the child to be evaluated at school. The evaluation can be done when the child is first suspected of having a disability (pre-placement evaluation) or when the child’s disability-related needs and support changes in one or more areas (re-evaluation).

Please contact your local School District’s Child Find program, or talk to your child’s school for more information.

For additional assistance navigating the special education system, South Carolina Autism Society has trained Parent Mentors to help with the process. Our Parent Mentors can help with IEP and 504 plans, handling behavioral issues, and other education-related issues. Contact our main office at 803-750-6988 to be connected with one of these staff members. This is a free service.  Learn more about our Parent School Partnership Program here.

Many adults report that finding someone to diagnose them with Autism is more difficult. In some cases, diagnosticians focus only on children, especially those that would be eligible for intensive early intervention. In other cases, professionals feel less qualified to diagnose adults, as the presentation may be different, it may be complicated by life history and co-occurring mental health conditions, and professional training in diagnosing adults with Autism is more limited. As above, we recommend starting with your primary care professional. If they do not have any recommendations, consult your local Autism Society affiliate for information on specialists who may diagnose adults. Adult neuropsychologists, adult neurologists, adult psychiatrists, and adult clinical psychologists are all individuals that may be able to diagnose an adult, if they have the training

and experience. Investigate these providers’ websites or profiles to determine if Autism is an area of expertise for them. It is very important to determine that the provider has extensive experience in diagnosing adults, specifically.

An adult evaluation will consist of review of the person’s developmental history, medical and psychological history, cognitive functioning, and Autism-specific tests, such as the ADOS. One important consideration is including someone in the evaluation who can report on early developmental history of the adult, such as a parent, care-provider, sibling, or relative. This information is often more difficult to obtain for adults, but it can help speed the process.

Educational determination.

There are two ways in which a child can be evaluated under the Individuals with Disabilities Education Act:

By request of parent or guardian.

The parent or guardian can request an evaluation by calling or writing the director of special education or the principal of the child’s school. Note: if the child attends a private or parochial school, the parent may need to contact the local public school district for this evaluation. It is important to place an evaluation request in writing and the parents should keep a copy to help track timing of the process. Suggestions for communicating with school systems:

  • Follow up on all telephone calls with a letter summarizing the conversation to allow for correction of misunderstandings.
  • Communicate both verbally and in writing to request meetings.
  • Keep copies of evaluations performed at school.

By request of school.

The school system may determine that an evaluation is necessary. If so, they must receive written permission from the parent before conducting the evaluation.
An evaluation should be conducted by a multidisciplinary team or group, which must include at least one teacher or other specialist with specific knowledge in the area of the suspected disability. IDEA mandates that no single procedure can be used as the sole criterion for determining an appropriate education program. The law also requires that the child be assessed in all areas related to the suspected disability, including but not limited to health, vision, hearing, communication abilities, motor skills, and social and/or emotional status.
If the parents disagree with the results of the evaluation, they may choose to obtain an independent evaluation at public or private expense. You may request a list of professionals that meet state requirements from your school, or you can choose one on your own. If the chosen professional meets appropriate criteria set up by the state, then the school must consider their evaluation in developing an Individualized Education Plan (IEP).

School re-evaluation.

An evaluation to consider educational Autism can be completed as part of an initial evaluation, or through the process of re-evaluation. For students who already receive special education services, a re-evaluation must take place at least every three years. It may, however, be conducted more often if the parent or a teacher makes a written request. An evaluation may also focus on a specific area of concern. A re-evaluation of all areas of suspected need is necessary if parents feel their child is not making adequate progress towards achieving their IEP goals.

Parents who feel their child’s disability category and related services and support should be changed must have a basis for requesting a re-evaluation. For example, a child may be exhibiting new skill deficits or challenging behaviors. It may be necessary to reassess their placement or develop new behavior techniques to address this area. As a first step, an evaluation by a specialist familiar with Autism-related behaviors could be requested. The IEP can then be changed to reflect the results of the evaluation.

For example, a child may have an annual goal to aim at increasing their language production and comprehension skills, but is not meeting the objectives developed in their IEP for this goal. The parent may wish to request a re-evaluation with a speech therapist who is knowledgeable about Autism. It may be determined from the results that an increase in the weekly number of hours of therapy is necessary.

A re-evaluation of all areas of suspected need may come prior to the scheduled annual IEP meeting. If the child has made significant progress since the last evaluation, the treatment, placement, and therapy recommendations may no longer be applicable. A re-evaluation addressing all areas would become the basis for a more appropriate IEP.

Parents may suggest that professionals with knowledge of Autism be present at the school for these evaluations.

The school does not have to use the suggested professional, but may appreciate the assistance in finding a qualified person. As explained above, if the parents disagree with the school’s evaluation, they do have a right to acquire an independent evaluation.

The IEP must be prepared collaboratively and agreed upon before initial placement in special education is made, rather than written after the fact to fit the special education determination.

Connect with us.

Reach out to us here at the South Carolina Autism Society for information and resources.