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How is Autism Diagnosed?

Autism spectrum disorder (ASD) can be difficult to diagnose.  ASD cannot be diagnosed with a specific medical test such as a blood test or x-ray like other medical conditions.  To diagnose ASD doctors must evaluate a child’s behaviors and development.  Accurately diagnosing ASD involves both developmental screening and comprehensive diagnostic evaluation.

At What Age Can ASD be Diagnosed?

ASD can be reliably diagnosed as young as two years of age and can sometimes be diagnosed at 18 months or younger.  However, many children do not receive a diagnosis until after four years of age.  Some individuals that experience milder symptoms may not be diagnosed until adolescence or young adulthood.

The earlier a diagnosis is received the more likely an individual can access appropriate intervention services.  It is crucial all children receive routine developmental screening and access appropriate interventions when developmental delays are identified.  Parents shouldn’t hesitate to share any concerns they have with their doctor or medical provider.

Can My Primary Care Doctor or Pediatrician Diagnose Autism?

Many guidelines and recommendations emphasize the need for a multi-disciplinary team to diagnose ASD.  Multi-disciplinary teams typically include a combination of child psychologists, developmental pediatricians, neurologists, and therapists.  This intensive approach is not required for an accurate ASD diagnosis in all cases and can lead to delays in evaluations and diagnosis.  In Missouri, a tiered approach to ASD diagnosis is recommended.

Using the recommended Tiered Approach, in Tier 1 a doctor (including primary care doctors and pediatricians) may be able to diagnose ASD if the symptoms and behaviors clearly indicate ASD and no other conditions.   Under Tier 2, individuals with milder or more complex symptoms should be evaluated by at least two medical professionals.  Under Tier 3, individuals with subtle and complex symptoms and co-existing conditions should be evaluated by multiple medical professionals. Parents and providers can learn more about the Tiered Approach in the Missouri Best Practice Guidelines for Screening, Diagnosis, and Assessment publications.

Primary care doctors and pediatricians should routinely screen all children for developmental delays at 9, 18, and 24 or 30 months during regular well-child visits.  Additional developmental screening may be necessary if a child is at high risk for developmental delays due to family history, genetic conditions, prematurity or other reasons.  In addition to regular developmental screenings, all children should be specifically screened for ASD at 18 and 24 months during regular well-child visits.  Additional ASD screenings may be necessary if the child is at high risk due to a family history of ASD, developmental delays, or if associated behaviors are present.

If your doctor is not routinely screening your child for developmental delays, ask that the screening be done.  If signs of delay are detected, you may be referred to a specialist or the doctor may be able to accurately diagnose ASD, depending on the presentation of symptoms and behaviors.