What are the next steps for a child diagnosed with autism at age 3, but showed no evidence of autism on the Autism Diagnostic Observation Schedule (ADOS)-2 assessment at age 6?

Comprehensive Reassessment and Diagnostic Clarification

This child requires a complete diagnostic re-evaluation by a multidisciplinary team to determine their current clinical status, as the discordant ADOS-2 result at age 6 indicates either diagnostic instability, developmental improvement, or an alternative neurodevelopmental diagnosis that was initially misidentified as autism. 1, 2

Understanding the Discordant Results

The situation you describe—an autism diagnosis at age 3 followed by a negative ADOS-2 at age 6—represents a critical diagnostic crossroads that demands careful interpretation:

Diagnostic Stability Considerations

• Diagnostic stability for ASD diagnosed at age 3 is generally very good (89-100%), particularly when the initial diagnosis was made using comprehensive evaluation methods including ADOS, clinical observation, and DSM criteria 2, 3
• However, diagnostic change does occur in approximately 10-13% of cases between age 3 and middle childhood, with some children no longer meeting ASD criteria at follow-up 3
• Children who lose their ASD diagnosis typically show significantly lower autism symptomatology and higher receptive language abilities at the initial assessment compared to those who retain the diagnosis 3

Patterns of Symptom Change

• Children with true ASD typically demonstrate improvement in Social Affect scores but worsening (unfolding) of Restricted and Repetitive Behavior scores over time 2
• If this child showed improvement across both domains rather than this characteristic pattern, it may suggest the initial diagnosis was incorrect or that they represent an atypical developmental trajectory 2

Immediate Next Steps

1. Comprehensive Clinical Re-Evaluation

Obtain a best estimate clinical (BEC) diagnosis through a multidisciplinary assessment that integrates multiple sources of information beyond the ADOS-2 alone 1, 4, 5:

• Direct behavioral observation in multiple settings (clinic, home, school) using standardized measures 1, 2
• Structured parent interview using tools like the Autism Diagnostic Interview-Revised (ADI-R) to assess developmental history and current functioning 1, 3
• Cognitive and language assessment using standardized measures like the Mullen Scales of Early Learning (MSEL) to evaluate developmental level 1, 2
• Review of the original age-3 diagnostic evaluation to understand what criteria were met and the quality of that assessment 2, 3

2. Consider Alternative Diagnoses

Children with autistic traits who score below ADOS cut-offs most commonly have communication disorders, mild intellectual disability, or ADHD rather than ASD 4:

• Communication disorders (CD) are the most frequent diagnosis in children with autistic traits but subthreshold ADOS scores, particularly in younger children 4
• Mild intellectual disability (mID) and ADHD are also common alternative diagnoses 4
• The ADOS alone cannot differentiate between different neurodevelopmental disorders, which is why comprehensive evaluation integrating multiple information sources is essential 4

3. Evaluate for Developmental Progress

Assess whether the child has made significant developmental gains that account for the change in presentation 2, 3:

• Examine receptive and expressive language development since age 3, as higher language abilities are associated with diagnostic change 3
• Evaluate nonverbal cognitive abilities, as developmental level accounts for changes in symptom presentation 2
• Document social communication skills in naturalistic settings, not just structured assessment 2

Critical Interpretation Points

ADOS-2 Limitations

• The ADOS-2 is not designed to be used as a standalone diagnostic tool—it must be integrated with clinical judgment, developmental history, and other assessments 1, 5
• ADOS-2 classification can have false negatives, particularly in children with higher cognitive and language abilities who have learned compensatory strategies 5, 3
• Individual ADOS items and domain scores do not reliably differentiate between different neurodevelopmental disorders, only between ASD and non-ASD 4

Possible Explanations for Discordance

1. Initial misdiagnosis: The age-3 diagnosis may have been incorrect, particularly if based on limited assessment methods or if the child had a communication disorder that mimicked ASD 4

2. True diagnostic change: The child may represent the 10-13% who genuinely no longer meet ASD criteria due to developmental progress and intervention response 3

3. Assessment limitations: The ADOS-2 at age 6 may have missed subtle but clinically significant ASD features, particularly in a verbally fluent child 3

4. Optimal outcome: Some children with early ASD show remarkable improvement and may achieve "optimal outcome" status, though this is relatively rare 3

Ongoing Management

Continued Monitoring

All high-risk children, including those with diagnostic uncertainty, require follow-up into middle childhood 3:

• Schedule reassessment at regular intervals (e.g., annually or biannually) to monitor developmental trajectory 3
• Maintain vigilance for emerging concerns in autism-related domains even if current diagnosis is unclear 3
• Document any developmental concerns noted by parents, teachers, or clinicians, as these may clarify the diagnostic picture 3

Treatment Implications

Continue evidence-based interventions targeting the child's specific developmental needs regardless of diagnostic label 1:

• Intensive behavioral interventions remain appropriate for children with social communication deficits, whether or not they meet full ASD criteria 1
• Speech-language therapy should be provided if communication delays persist 4
• Educational supports should be based on functional impairments rather than diagnostic category alone 1

Common Pitfalls to Avoid

• Do not rely solely on the ADOS-2 result to make or unmake an ASD diagnosis—comprehensive clinical judgment integrating multiple sources is essential 1, 4
• Do not assume diagnostic stability without thorough re-evaluation, as 10-13% of children show diagnostic change 3
• Do not delay intervention while awaiting diagnostic clarity—treat the child's functional impairments regardless of label 1
• Do not dismiss the original diagnosis without understanding what led to it and whether assessment quality was adequate 2, 3
• Do not fail to consider alternative neurodevelopmental diagnoses, particularly communication disorders, which are the most common explanation for autistic traits with subthreshold ADOS scores 4