ASQ Screening Ages
The Ages and Stages Questionnaire (ASQ) should be performed at 9,18, and 30 months of age (or 24 months as an alternative to 30 months), combined with developmental surveillance at all well-child visits. 1
Recommended Screening Schedule
The American Academy of Pediatrics guideline explicitly recommends:
- 9 months of age - First formal ASQ screening
- 18 months of age - Second formal ASQ screening
- 30 months of age (or 24 months as alternative) - Third formal ASQ screening
This recommendation applies to standardized developmental screening tools in general, with the ASQ specifically mentioned as one of the preferred parent-completed instruments 1.
Rationale for These Specific Ages
These three time points are strategically chosen because:
- Early detection is critical: Up to 50% of children with developmental delays are missed before kindergarten entry, even though most show delays by 2 years of age 1
- Clinical judgment alone is inadequate: Physician impression alone would miss 45% of children eligible for early intervention 1
- Surveillance alone has poor sensitivity: Checklists and clinical observation without standardized tools fail to detect many delays 1
Important Implementation Details
The ASQ-3 demonstrates strong psychometric properties:
- Overall sensitivity: 85%
- Overall specificity: 86%
- Strong test-retest reliability (r = 0.94)
- Feasible in busy clinical settings without impeding office flow 1
Key caveat: While these are the recommended ages for formal screening, developmental surveillance (informal monitoring through history and observation) should occur at every well-child visit, not just at screening ages 1.
Practical Considerations
The ASQ is specifically recommended as a parent-completed tool rather than a directly administered instrument, which makes it more practical for busy primary care settings 1. The 30-month visit faces reimbursement challenges in some settings, which is why 24 months is offered as an acceptable alternative 1.