At the present time, there are no medical test that can diagnose autism. However, specially-trained physicians and psychologists can administer autism-specific behavioral evaluations. Healthcare professionals also rely on the observations of parents, physicians and therapists to learn as much as they can about the child in question in order to make a diagnosis.

By studying a core group of three behaviors, they can gain a better understanding of the child’s tendencies and determine if they coincide with this disorder. They will study the child’s level of social interaction, and observe the child to learn how they interact with both peers and parents. Secondly, they will focus on verbal interactions, as there may be some difficulty for the child to vocalize their needs and converse, (they may rely on communicating through grunts and pointing). Lastly, doctors will look at repetitive behaviors and if a child has a narrow field of interests that may be exclusive from others.

Autism can be detected, and even reliably diagnosed, in a child as early as 18 months. From the perspective of neuroscience, there has been a tremendous amount of evidence to support early intervention as the best chance to change the developing brain. Behaviorally, early intervention is very important to help in keeping negative behaviors from becoming ingrained and persistent as the child continues to grow. By intervening early to prevent certain behaviors and which will create better outcomes for the future. Children that receive individualized therapy at this young age will be better prepared for integration into group situations such as school, where they will experience more socialization in a group setting.

Various studies have pointed out to the fact that the ‘wait and see’ method can result in missed opportunities for early intervention, and is, therefore, not recommended. Every child with autism spectrum disorder possesses unique talents. It is strongly recommended that parents ensure that their child is diagnosed early and receives the appropriate help, so their child can truly tap into their potential.

Diagnosis in children generally happens in 2 stages:

1. Developmental screening during regular doctor checkups

Developmental screening is a short test that can help identify if children are learning basic skills when they should, or if they might have delays. The American Academy of Pediatrics recommends that all children be screened for developmental delays at their 9-, 18-, and 24- or 30-month well-child visits and specifically for autism at their 18- and 24-month well-child visits.

If the child is high risk for developmental problems or ASD, more screening might be recommended. High risk children include those with older parents, those who have a family member with ASD, or if they were born with low birth weight.

Parents’ observations are important during the screening process. The doctor may ask them a series of questions that give them additional information, along with the doctor’s own screening, combining parental feedback with information from ASD screening tools, and with his or her observations of the child.

2. Continued evaluation

This second evaluation is with a team of doctors and other health professionals who are experienced in diagnosing ASD. It may be that the child is diagnosed with a developmental delay which will require further testing to determine the specific issue. This team may consist of a developmental pediatrician, a child psychologist, a neuropsychologist, and / or a speech pathologist. This evaluation is designed to assess the following: language and cognitive abilities, age appropriate skills (e.g., eating, toileting, dressing). It may include looking at the child’s behavior and development and interviewing the parents to learn more about their own observations. It may also include a hearing and vision screening, neurological testing, genetic testing, and other medical testing.

These tests, more specifically, include:

Behavioral assessments. Various guidelines and questionnaires are used to help a doctor determine the specific type of developmental delay a child has. These include:

  • Clinical observations. Observation of developmentally delayed child in different situations may occur. The doctor will assess the child in these settings and the parents may be consulted to learn if certain behaviors are usual for the child in those circumstances.
  • Medical history. During the medical history interview, a doctor asks general questions about a child’s development, such as whether a child will point out objects to their parents. Young children with autism often point to items they want, but do not have a tendency to point to show parents an item and then check to see if parents are looking at the item being pointed out.
  • Autism diagnostic guidelines. The American Association of Childhood and Adolescent Psychiatry (AACAP) has established guidelines for diagnosing autism. The criteria are designed so a doctor can evaluate a child’s behavior relating to core symptoms of autism.
  • Developmental and intelligence tests. The AACAP also recommends that tests be given to evaluate whether a child’s developmental delays affect his or her ability to think and make decisions.

Physical assessments and laboratory tests. Additional testing may take place to determine whether a physical problem may be causing symptoms. These tests include:

  • Physical exam to determine whether a child has a normal growth pattern. This may include weight and height measurements and measuring head circumference.
  • Hearing tests, to determine whether hearing problems may be causing developmental delays, especially those related to social skills and language use.
  • Testing for lead poisoning, and especially for a condition called pica (in which a person craves substances that are not food, such as flecks of paint or dirt). Children with developmental delays usually continue putting items in their mouth after this stage has passed in normally-developing children. Consuming non-food items can result in lead poisoning; therefore, it is important to get this diagnosed and treated as soon as possible.

Additional lab tests may be performed for specific reasons, such as chromosomal analysis, due to intellectual disability present in the child or there is a family history of intellectual disability. For example, Fragile X syndrome, which causes autistic-like behaviors as well as a range of below-normal intelligence problems can be identified with a chromosomal analysis. An electroencephalograph (EEG), may be performed if there are symptoms of seizures, including a history of staring spells or if a person reverts to less mature behavior (developmental regression). An MRI, may be done if there are signs of differences in the structure of the brain.

  • Talks or babbles with unusual tone, e.g., their voice might not vary in pitch, tone, or volume.)
  • Low enthusiasm for learning or exploring new things
  • Carries around unusual objects for an extended period of time (and be distressed if they are unable to have the object/s.)
  • Plays with toys in an unusual manner, e.g., being particularly focused on spinning the wheels, rather than playing with the toy as a whole
  • Overly fussy and seem unable to be soothed by common calming practices, e.g., being held or spoken to in a calming voice
  • Appears to have unusual sensory sensitivities, e.g., sensitivities to a certain sounds or the way an object looks, or an aversion to common food for children that age, such as Cheerios or a banana
  • Unusual body or hand movements, e.g., flapping motions with arms, repetitive unusual body poses or stances after performing a task

There are a number of developmental screening tools that may be administered by healthcare providers, and even parents. Some of these include:

  • Ages and Stages Questionnaires (ASQ)
  • Modified Checklist for Autism in Toddlers (M-CHAT)
  • Communication and Symbolic Behavior Scales (CSBS)
  • The Childhood Autism Rating Scale (CARS)
  • Parent’s Evaluation of Development Status (PEDS)
  • Screening Tool for Autism in Toddlers and Young Children (STAT)
  • Observation tools such as the Autism Diagnostic Observation Schedule (ADOS-G)
  • The Autism Diagnostic Interview – Revised (ADI-R)

During the testing process, it is important for all parties involved to communicate and work together. The Autism Society of America urges parents to use these helpful tips when going through the diagnosis process.

  • Stay informed.Research as much as you can about your child’s disorder. Then when you are talking to healthcare professionals, you will be positioned to ask questions. If you find something isn’t clear, be sure to ask for clarification.
  • Be prepared. Be prepared for meetings with doctors, therapists and school personnel. Write questions and concerns down ahead of time, so you are ready when the meeting takes place. Be sure to write down – or log, in some way – all of their feedback and answers to your questions.
  • Be organized.Many parents find it useful to keep a notebook chronicling their child’s diagnosis and treatment as well as meetings with professionals.
  • Communicate.Open communication is so important to this process. If you don’t agree with a professional’s recommendation, for example, say specifically why you don’t or ask for clarification to gain a better understanding of the situation.