Autism Spectrum Disorder Diagnosis and Management

Initial Screening and Diagnostic Confirmation

The American Academy of Pediatrics recommends screening all children at 18 and 24 months using validated tools like the M-CHAT during routine well-child visits, even without specific concerns 1
Key early signs to identify between 12-24 months include reduced eye contact and social smiling, limited nonverbal behaviors to initiate shared experiences, atypical object use, and repetitive behaviors 1
Diagnostic confirmation must be performed by trained professionals using objective criteria with standardized measures including the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2, sensitivity 91%, specificity 76%) and Autism Diagnostic Interview (sensitivity 80%, specificity 72%) 1

Every child with suspected ASD must have a formal audiogram to rule out hearing loss that could mimic ASD symptoms before proceeding with further evaluation 1, 2, 3
Establish a primary care medical home for every individual with ASD to coordinate diagnostic testing and ongoing care 1, 3, 4

A genetic consultation should be offered to all persons/families with ASD, as a thorough clinical genetics evaluation identifies an underlying etiology in 30-40% of individuals 2, 3
Evaluation by a clinical geneticist/dysmorphologist remains high-yield and low-cost for identifying syndromic versus isolated ASD through examination for dysmorphic features and family history analysis 2, 3
Order the following genetic tests with expected diagnostic yields: Chromosomal microarray (CMA): 10% yield, Fragile X DNA testing: 1-5% yield, High-resolution karyotype: 3% yield 2
MECP2 gene testing in females has a 4% yield in females with ASD, and PTEN gene testing has a 5% yield in patients with head circumference >2.5 standard deviations above the mean 2

Intensive behavioral interventions are first-line therapy, particularly for children 5 years or younger, focusing on improving language, play, and social communication skills with small to medium effect sizes 1
Pharmacotherapy is reserved for co-occurring conditions and specific symptoms, not core ASD features 1

Provide genetic counseling to all families regardless of whether an etiology is identified 1, 4
For families without identified etiology, use empiric recurrence risk data: Full sibling recurrence risk: 3-10%, Modified by sex: 7% if affected child is female, 4% if affected child is male, With two or more affected children: at least 30% recurrence risk 4
Schedule periodic reevaluations for patients without a definitive etiology, as diagnostic technology and understanding continue to evolve 2, 4

Do not delay diagnosis due to misconceptions about presentation, particularly in adults or atypical cases 5
Do not order extensive genetic testing without clinical geneticist evaluation first, as the stepwise approach with higher-tier tests having greater diagnostic yield is more cost-effective and better tolerated by families 3, 6
Do not fail to provide recurrence risk information to families, as this is essential for family planning and understanding 1, 4

The American Academy of Child and Adolescent Psychiatry recommends conducting direct observation focusing specifically on social interaction patterns and restricted/repetitive behaviors, with modifications based on the child's developmental level, as part of a comprehensive multidisciplinary assessment 7
A detailed developmental history, including timing of symptom onset, regression history if present, response to previous interventions, and family psychiatric history, should be obtained as part of the diagnostic process, according to the American Academy of Child and Adolescent Psychiatry 7
The American Academy of Child and Adolescent Psychiatry suggests performing a physical examination, including a Wood's lamp examination for tuberous sclerosis signs, as part of the diagnostic workup 7

The American Academy of Child and Adolescent Psychiatry recommends performing a physical examination, including a Wood's lamp examination for tuberous sclerosis signs, as part of the diagnostic workup 7

The American Academy of Child and Adolescent Psychiatry suggests that chromosomal microarray (CMA) analysis has a 10% diagnostic yield and is now the standard of care for initial evaluation 7
Additional genetic testing, such as EEG, neuroimaging, metabolic testing, or other genetic studies, should only be ordered when specific clinical features warrant them, according to the American Academy of Child and Adolescent Psychiatry 7
The American Academy of Child and Adolescent Psychiatry recommends considering Landau-Kleffner syndrome evaluation (EEG) when marked aphasia develops 7

The American Academy of Child and Adolescent Psychiatry suggests conducting cognitive testing and adaptive skills measurement for treatment planning, as these frame social-communication difficulties relative to overall developmental level 7
The American Academy of Child and Adolescent Psychiatry recommends expecting considerable scatter in intelligence test results, with possible "splinter skills" or savant abilities in specific domains 7
Assessing for areas of intense, circumscribed interests in higher-functioning individuals is also recommended by the American Academy of Child and Adolescent Psychiatry 7