# How is autism diagnosed in children, and what happens at an evaluation? > The steps from first worry to diagnosis, who does evaluations, what happens on the day, and how to prepare. URL: https://theautismkit.com/guides/how-is-autism-diagnosed By The Autism Kit team · Reviewed by [BCBA NAME], BCBA · Updated 2026-09-27 **Short answer:** There's no blood test for autism. It's diagnosed by specialists who look at your child's development and behavior: they talk with you, watch your child play and communicate, and often use structured activities and questionnaires. The usual path is developmental monitoring, screening at the 18- and 24-month checkups, then a full evaluation if there are concerns. **Key takeaways** - There is **no medical test**. Specialists diagnose by looking at **development and behavior**. - The usual path: **monitoring → screening → full evaluation**. - Pediatricians screen at **18 and 24 months**. You can ask sooner. - You can **start early intervention or school support** while you wait. ## What are the steps to an autism diagnosis? The CDC describes three steps.[1] 1. **Developmental monitoring.** You and your child's doctor watch how your child plays, learns, talks and moves over time. 2. **Developmental screening.** Short questionnaires at well-child visits compare your child with other children the same age. Autism-specific screening is recommended at **18 and 24 months**.[2] 3. **Developmental evaluation.** If screening or your concerns point to autism, a specialist does a full evaluation. Screening can't diagnose autism. It tells you whether a closer look is needed.[2] More on that in [Is there an online autism test for my child?](https://theautismkit.com/guides/autism-test-for-kids) ## Who can diagnose autism? Evaluations are done by trained specialists, such as developmental pediatricians, child psychologists, child psychiatrists and pediatric neurologists. Speech-language pathologists and occupational therapists are often part of the team.[1] Your pediatrician can refer you. To find one yourself, see [How do I find an autism evaluation near me?](https://theautismkit.com/guides/finding-an-autism-evaluation) ## What happens at an autism evaluation? Every clinic is a little different, but most evaluations include:[3] - **A conversation with you** about pregnancy, development, milestones, behavior, sleep, eating and family history. - **Watching your child play and communicate**, often with structured activities designed to show social communication and play. - **Questionnaires** for you, and sometimes for teachers or daycare staff. - **Other checks**, like hearing, speech and language, or thinking and learning skills, to get the full picture. At the end, or at a follow-up visit, the clinician explains what they found, whether your child meets criteria for autism, and often a **level** describing support needs. See [What are the levels of autism?](https://theautismkit.com/guides/levels-of-autism) **Prepare your child with pictures.** A few photos of the building, the room and the person you'll meet, in the order they'll happen, can make a new place feel less surprising. ## How do I prepare for the evaluation? **Try:** - Bring written examples of what you've noticed - Bring short videos of typical and hard moments - Bring reports from school, daycare or therapists - Bring snacks, a comfort item and something to do while waiting **Skip:** - Coaching your child to "behave" differently than usual - Waiting until the day to write down concerns - Leaving without knowing the next step ## Can we get help before the evaluation? Yes, and you don't have to wait: - **Under 3:** every state has a free early intervention program that can evaluate your child's development. Children don't need an autism diagnosis to qualify.[5] - **3 and older:** you can ask your public school district, in writing, to evaluate your child for special education services.[4] These programs look at what your child needs, not only at a diagnosis. **Call your doctor sooner if....** your child loses words or skills, stops responding to people, or you have safety concerns. Don't wait for a scheduled evaluation. Free printable: [Free printable: appointment notes](https://theautismkit.com/printables/appointment-notes.pdf) ## What can I do this week? - [ ] Ask your pediatrician for a screening or referral - [ ] Contact early intervention (under 3) or your school district (3+) - [ ] Start your appointment notes - [ ] Pick one routine to support at home While you wait, the [2-minute quiz](https://theautismkit.com/start) gives you one plan for the hardest part of your child's day. ## Common questions ### How young can a child be diagnosed with autism? By age 2, a diagnosis by an experienced professional can be considered reliable. Some children are diagnosed earlier, and many are diagnosed later. ### Does my child need a diagnosis to get help? Not always. Children under 3 can be evaluated for early intervention, and school districts evaluate children 3 and older for special education, based on their needs rather than a medical diagnosis. Insurance-funded therapies often do require a diagnosis. ### How long does an autism evaluation take? It varies: some are done in one visit of a few hours, others over several appointments. Ask the clinic what to expect and whether they'll need school or daycare reports. ## Sources 1. CDC: Diagnosing autism spectrum disorder. https://www.cdc.gov/autism/diagnosis/index.html 2. CDC: Autism screening for healthcare providers. https://www.cdc.gov/autism/hcp/diagnosis/screening.html 3. HealthyChildren.org (American Academy of Pediatrics): Diagnosing autism. https://www.healthychildren.org/English/health-issues/conditions/Autism/Pages/Diagnosing-Autism.aspx 4. Center for Parent Information and Resources: Evaluating children for disability (IDEA). https://www.parentcenterhub.org/evaluation/ 5. Early Childhood Technical Assistance Center: State Part C (early intervention) coordinators. https://ectacenter.org/contact/ptccoord.asp General guidance, not a diagnosis or treatment plan. Talk with your pediatrician or a developmental specialist about your child's care.