Clinically reviewed by Sarah A. Rebuelta, MS, BCBA, GA-LBA, Board Certified Behavior Analyst and early intervention specialist with nine years of clinical experience.
The pediatrician said "let's keep an eye on it." That was four months ago. Your child still isn't pointing, still isn't responding to their name, and the gap between them and the cousins at the last family dinner is no longer subtle. You are past watching. You want an answer.
Here is the plain-English version. How to get an autism diagnosis comes down to five steps that look nearly identical in every state: a developmental screening at the pediatrician's office, a referral, a comprehensive evaluation appointment with a qualified clinician, a written diagnostic report, and then insurance authorization for therapy. An autism diagnosis is a clinical judgment made by a licensed professional who observes your child, interviews you, and compares what they see against the DSM-5-TR criteria. There is no blood test. What changes from Georgia to Maryland is not the medical standard. It is the door you walk through, who is allowed to sign the report, and how long the line is behind that door.
Already past the waiting stage? Blossom ABA evaluates and treats under one roof across all five states, which means no second waitlist between the report and the first therapy session. See how our autism evaluation and diagnosis process works, or call (877) 315-1069 and ask what the current wait looks like where you live.
How to Get an Autism Diagnosis: The Five Steps Every State Shares
Every family in Blossom's five states moves through the same sequence. The details shift. The order does not.
Step 1: Screening. The American Academy of Pediatrics recommends standardized autism-specific screening at the 18-month and 24-month well-child visits, layered on top of developmental surveillance at every visit. The M-CHAT-R/F is the tool most pediatricians use.
Step 2: Referral. A positive screen, or a parent concern the pediatrician takes seriously, should trigger two referrals at once: one for a diagnostic evaluation, one for early intervention or school services. Ask for both in the same visit.
Step 3: The evaluation. A qualified clinician conducts direct observation, developmental testing, and a caregiver interview.
Step 4: The report. You receive a written diagnostic report naming the diagnosis and the recommended services. This document is what unlocks funding.
Step 5: Authorization. Your insurer reviews the report and approves therapy hours.
Most parents underestimate how much of the timeline sits in steps 2 and 3. That is where the waiting happens.
If you are still at the "is this something or nothing" stage, the early signs that warrant an evaluation are worth reviewing before your next appointment. Walking in with written observations moves the conversation faster than a general worry.
Who Can Diagnose Autism, and Who Cannot
Parents lose months to this question. A teacher, a daycare director, a speech therapist, and a school psychologist can all raise a concern. None of them can issue the diagnosis that an insurance company will accept.
The professionals qualified to diagnose autism in children are:
Developmental-behavioral pediatricians — the specialist most often named on a referral, and the one with the longest waitlists
Child psychologists and neuropsychologists — licensed clinicians who administer instruments like the ADOS-2
Child psychiatrists
Pediatric neurologists
General pediatricians with autism-specific training, in a growing number of practices
One clarification saves enormous confusion later. A school district can find your child educationally eligible under the autism category. That eligibility supports an IEP. It is not a medical diagnosis, and most insurers will not authorize ABA therapy on the strength of a school eligibility letter alone. Families often need both documents for different purposes.
What Actually Happens During an Autism Evaluation
A comprehensive autism evaluation usually runs two to four hours, sometimes split across two visits. Expect four components.
Caregiver interview. You will answer detailed questions about pregnancy, milestones, language, play, feeding, sleep, and behavior. Bring your notes. Bring video of your child at home if you have it.
Direct observation. The clinician plays with your child using structured tasks, frequently the ADOS-2, watching how they share attention, respond to their name, use gestures, and handle transitions.
Developmental and cognitive testing. Tools like the Mullen Scales or a language assessment establish where your child is functioning across domains.
Record review. Pediatric charts, hearing screening results, prior therapy notes, and daycare or preschool reports.
Your child does not need to prepare. There is nothing to study and nothing to pass. Feed them beforehand, bring the comfort item, and schedule around the nap.
How Long Does It Take to Get an Autism Diagnosis?
Nationally, the answer is far too long. CDC's Autism and Developmental Disabilities Monitoring Network reported that the median age of earliest known autism diagnosis was 49 months, roughly age four, even though CDC also notes that a diagnosis by an experienced professional can be considered reliable by age two. That gap of two years is not a medical limitation. It is a scheduling one.
Two clocks run in parallel, and most families only start one.
The federal early intervention clock. For children under three, IDEA Part C requires that the screening, initial evaluation, and initial IFSP meeting all be completed within 45 days of referral. This clock starts on the referral date, not on the date you sign consent. It is the same in all five states.
The diagnostic clinic clock. This one has no federal deadline. Hospital-based developmental clinics in major metros commonly quote waits measured in many months. Private practices and diagnostic-plus-therapy providers are often significantly faster.
The practical takeaway: call early intervention the same week you call the diagnostic clinic. Early intervention services do not require a completed autism diagnosis. Your child can be receiving speech and developmental support while the diagnostic appointment is still pending, and it costs you nothing to run both tracks at once.
Where to Start in Each State
The medical criteria are federal. The intake phone number is not.
Georgia
Under age three, the entry point is Babies Can't Wait, Georgia's Part C program administered through the Department of Public Health district offices. Age three and up, the referral goes to your local school district's special education office for educational eligibility, and separately to a developmental clinic or licensed psychologist for the medical diagnosis. Families in metro Atlanta face the longest institutional waits in the state. Georgia's Katie Beckett pathway can matter for children whose family income would otherwise disqualify them from Medicaid, so it is worth reviewing the Katie Beckett Waiver rules early rather than after the diagnosis lands.
Tennessee
Start with the Tennessee Early Intervention System (TEIS) for children under three. TEIS accepts direct parent referrals, which means you do not need to wait for the pediatrician to make the call. For diagnostic evaluations, Tennessee families frequently work through developmental clinics affiliated with academic centers, including the Vanderbilt Kennedy Center, one of the federally designated University Centers for Excellence in Developmental Disabilities. Demand at academic centers is high, so pair that referral with a private option.
Virginia
Virginia's Part C program is the Infant & Toddler Connection of Virginia, organized by local system. Referrals go to your regional office and, like Tennessee, parents can self-refer. For school-age children, Virginia districts run their own eligibility process on a state timeline. The medical diagnosis still comes from a licensed psychologist, developmental pediatrician, psychiatrist, or neurologist.
North Carolina
North Carolina routes early intervention through the NC Infant-Toddler Program, delivered by regional Children's Developmental Services Agencies (CDSAs). North Carolina also hosts the TEACCH Autism Program at UNC-Chapel Hill, one of the longest-running autism programs in the country and a recognized reference point for diagnostic practice. CDSA intake and a diagnostic clinic referral should happen in the same week.
Maryland
Maryland's Part C system is the Maryland Infants and Toddlers Program, administered locally by each county and Baltimore City. Maryland families also have access to the Kennedy Krieger Institute, a Johns Hopkins-affiliated center whose diagnostic waitlists reflect that reputation. As in the other four states, the county program and the diagnostic clinic are separate applications.
Across all five states, our ABA therapy services begin the same way once a report exists: an authorization request, a treatment plan, and a start date.
A Real Scenario: How the Timeline Actually Plays Out
A Tennessee mother noticed her 22-month-old son had stopped using the six words he had at 18 months. Her pediatrician suggested waiting until the two-year visit. She did not wait.
She called TEIS herself on a Tuesday and asked her pediatrician's office to fax a referral to a developmental clinic the same week. TEIS completed its evaluation and IFSP meeting inside the federal 45-day window, and her son started speech therapy in under two months. The developmental clinic offered a diagnostic appointment five months out. She took it, and kept a cancellation-list slot at a second provider.
Her son received his autism diagnosis at 27 months. Because early intervention had already been running for three months, his ABA authorization came through quickly and therapy began without another gap. Had she waited for the diagnosis before doing anything else, he would have started services close to his third birthday, after aging out of Part C entirely.
The lesson is not that she got lucky. It is that she ran both clocks.
What You Need Before ABA Therapy Can Begin
Once the diagnosis is in hand, insurers generally want a specific package:
The written diagnostic report with the DSM-5-TR diagnosis and date
A referral or prescription for ABA from the diagnosing clinician or pediatrician
Proof of active coverage and, in many plans, a completed prior authorization
A behavior assessment and treatment plan written by a BCBA after intake
Every state Blossom serves has an autism insurance mandate applying to state-regulated plans, though self-funded employer plans fall under federal ERISA rules and follow their own terms. Medicaid is a separate track with its own documentation requirements. Our insurance guide breaks down what each state requires and where the exceptions sit.
Two questions come up immediately after approval. First, how much therapy: the answer depends on assessment results and family goals, not a fixed number, and the research behind recommended hours is more nuanced than the 40-hour figure parents hear repeated. Second, where therapy happens: the tradeoffs between in-home and center-based ABA look different for a two-year-old than for a five-year-old heading to kindergarten.
Start Both Clocks This Week
The single most useful thing a parent can do is refuse to run one step at a time. Call early intervention. Ask the pediatrician for a diagnostic referral. Get on more than one waitlist. Ask each clinic about cancellation lists. None of these depend on each other, and none of them require permission.
Every month a child spends on a waitlist is a month of early intervention nobody gets back. That is the real cost of the four-year national median, and it is the one part of this process a parent can actually change.
Blossom ABA runs the evaluation and the therapy under one roof across 5 states mentioned above. One intake. One clinical team. No handoff between the report and the first session.
Walk our team through what you have been noticing at home using the contact page, and ask for a direct evaluation date in your state. Tell us what changed, when it changed, and what your pediatrician said. You will get back a real timeline, a clear read on what your plan covers, and the name of the clinician who would see your child.
Frequently Asked Questions
Who can diagnose autism in a child?
A developmental-behavioral pediatrician, child psychologist, neuropsychologist, child psychiatrist, or pediatric neurologist can issue a medical autism diagnosis. School psychologists can determine educational eligibility but not a medical diagnosis.
How long does it take to get an autism diagnosis?
Early intervention evaluations must be completed within 45 days of referral under federal law, while diagnostic clinic waits often run several months. CDC data show the median age of earliest diagnosis nationally is around four years old.
How do I get an autism diagnosis for my child if my pediatrician says to wait?
You can request a referral directly, and in states like Tennessee and Virginia you can self-refer to the early intervention program without a physician. A second opinion is always an option.
What age can a child be diagnosed with autism?
Autism can be reliably diagnosed by age two, and signs are sometimes identified as early as 18 months. Screening is recommended at the 18-month and 24-month well-child visits.
Can my child start ABA therapy without an autism diagnosis?
Insurance-funded ABA generally requires a written diagnostic report. Early intervention services such as speech and developmental therapy do not require a diagnosis and can begin while you wait.
Does insurance cover an autism evaluation?
Most plans cover diagnostic evaluations as a medical service, though prior authorization and network status vary. Coverage rules differ between state-regulated plans, self-funded employer plans, and Medicaid.
About the Reviewer
Sarah A. Rebuelta, MS, BCBA, GA-LBA is a Board Certified Behavior Analyst and Georgia Licensed Behavior Analyst with nine years of clinical experience and an MS in Applied Behavior Analysis. She specializes in early intervention, helping young children build communication, daily living, social, and emotional regulation skills that carry across home, school, and community settings. She reviewed this article for clinical accuracy.
