How Early Can You Test for Autism?
When you’re noticing differences in your child’s development, such as fewer words than expected, difficulty engaging, or reactions that seem a little different from other children, it’s completely understandable to have questions. One that often comes up is how early professionals can reliably identify autism in young children. Parents usually want to know what age they can seek answers, what signs to pay attention to, and when it makes sense to get an evaluation.
Key Takeaways
Autism can often be reliably identified between 18 and 24 months, and early signs may appear even earlier.
Early evaluation can provide clarity about your child's development and opens the door to early intervention services, which can significantly support growth.
Noticing signs does not automatically mean a child has autism, but it is a helpful signal to seek a professional assessment.
You do not need to wait for a pediatrician to bring up concerns. If something feels “off,” it’s appropriate to pursue an evaluation as soon as questions arise.
Autism Can Be Reliably Identified Earlier Than Many Parents Realize
Research shows that signs of autism can often be observed before age 2, and for many children, a diagnosis made between 18 – 24 months is quite stable. In one large study of more than 1,200 toddlers, the “diagnostic stability” (how likely the diagnosis was to stay the same over time) was about 84% for autism.
Early evaluation for autism can make a meaningful difference. It helps you understand your child’s strengths, identify developmental needs, and connect with early supports when they can have the most impact.
What Are the Early Signs of Autism?
Every child develops at their own pace, so noticing one or two of these signs doesn’t automatically mean your child has autism. Still, if you’re seeing several of these patterns, it’s reasonable to explore an evaluation:
Limited eye contact
Not responding to their name consistently
Delayed speech or very few gestures (like pointing or waving)
Preferring to play alone rather than with others
Repetitive movements (rocking, hand-flapping, spinning objects)
Strong interest in specific objects or parts of toys
Sensitivity to sounds, textures, or lights
Difficulty with transitions or changes in routine
Remember: noticing signs is not the same as receiving a diagnosis—it’s simply motivation to learn more.
ASD Screening vs. Diagnostic Testing: What’s the Difference?
Parents often hear the terms screening and diagnostic evaluation, and while they’re connected, they’re not the same.
Autism Screenings
Screenings are quick questionnaires or checklists your pediatrician may use during well-child visits—often at 18 and 24 months. These tools identify whether your child should be referred for a full evaluation. They do not diagnose autism.
Diagnostic Evaluations
If screening raises concerns (or if you already have concerns), a licensed psychologist or developmental specialist conducts a comprehensive assessment. This may include:
Observing your child during play
Reviewing developmental milestones
Talking with you about behaviors you’ve noticed at home
Using standardized tools that assess communication, social interaction, and behavior
Screening for other developmental differences
This thorough evaluation is what leads to a formal diagnosis—if appropriate—or provides clarity about other developmental needs.
How Early Should You Test Your Child for Autism?
If you have concerns, the answer is simple: as soon as you notice the signs.
You do not need to wait until a certain age or until your pediatrician brings it up.
Early evaluation leads to early support—and toddlers’ brains are especially responsive to learning during these years.
What If a Child Is Too Young to Diagnose?
Sometimes, an evaluation may find that a child is showing some early signs but is not yet meeting full criteria for autism. In these cases, professionals often use terms such as:
“At risk for autism”
“Developmental delay”
“Social communication concerns”
Even without a formal diagnosis, your child may still qualify for early intervention therapies, which can help support communication, social connection, and adaptive skills while they continue to grow.
What Is Early Intervention for Autism?
One of the biggest benefits of early testing is access to early intervention services—specialized supports for infants and toddlers. These programs can:
Strengthen communication skills
Build social engagement
Support emotional regulation
Promote developmental progress
Research consistently shows that earlier support can lead to meaningful improvements over time.
You’re Not Alone
Many parents feel unsure, overwhelmed, or even guilty for wondering whether their child might have autism. These feelings are common, but reaching out for answers is a loving, proactive step. An evaluation does not label your child. It helps you understand them more clearly, support them more effectively, and access the resources they deserve.
Autism can often be reliably tested between 18–24 months, and early signs may appear sooner. If something feels different or unclear in your child’s development, you don’t have to wait. Seeking an evaluation early gives your child the best opportunity for support—and gives you peace of mind.
If you’d like help navigating early developmental questions or scheduling an autism evaluation for your child, please contact me.
