Getting Your Child Assessed for Autism:
A Parent's Step-by-Step Guide

When you first start wondering whether your child might be autistic, one of the most confusing parts is simply not knowing where to begin. The NHS pathway is not always explained clearly. Different areas work differently. GPs sometimes seem uncertain themselves. And the internet serves up a mix of helpful information and outdated or inaccurate advice that makes it hard to get your bearings.

This guide is my attempt to set out the process clearly, based on what the NHS, the National Autistic Society, and NICE say. Ella went through an autism assessment when she was four. Since then I've learned a lot more about how the process works across different areas, and I've tried to distill that into something practical here. If you're also wondering about an ADHD assessment for your child, that process is similar but different enough to warrant its own guide.

Before anything else: trust your instincts

If you're reading this, something has probably already prompted concern. That might be something you've noticed at home, or something flagged by school or nursery, or a health visitor, or another parent. Whatever it is: your observations matter. Parents know their children, and the concerns that bring families to an autism assessment are nearly always based on real, consistent patterns of behaviour rather than a single incident.

The assessment process can take a long time. Knowing this upfront makes it easier to plan. A diagnosis does not change who your child is. It gives language to what you've likely already sensed, and it opens doors to support, EHCPs, DLA, and the kind of adjustments that can make a real difference to daily life.

Step 1: Starting the referral

The most common starting point is your GP. You do not need to have a formal diagnosis or a psychiatrist's letter to ask for a referral. You simply need to describe your concerns clearly and ask for your child to be referred for an autism assessment.

What if the GP refuses?

It happens. Some GPs are unsure about autism in girls, in children who mask well at school, or in children who seem to cope in some settings but fall apart at home. If your GP declines to refer, ask them to explain exactly why and what they would need to see in order to reconsider. You can request a second opinion from a different GP at the same surgery.

The National Autistic Society has detailed guidance on your rights in this situation on their website (autism.org.uk). You can also ask your SENCO to provide school observations in writing, which strengthens the case for referral. A private assessment is an option too, though there are significant costs involved — see below.

Right to Choose: what it is and how it works for children

In England, if your GP agrees that an autism assessment is clinically appropriate, you have a legal right under the NHS Choice Framework to choose which NHS-contracted provider carries out that assessment. This is known as Right to Choose (sometimes referred to as RTC or Patient Choice).

Right to Choose applies to autism assessments for children in England. It does not apply in Scotland, Wales or Northern Ireland, where different arrangements exist. You cannot self-refer under Right to Choose. The referral must come from your GP or another eligible professional.

What the autism assessment involves

An autism assessment for a child is not a single test. It is a multi-stage process that brings together information from you, from school, and from the assessing clinicians. The exact format varies between services and depends on your child's age, but the core elements are similar across NHS and most private pathways.

Before the assessment: questionnaires and school reports

Most services send out questionnaires before any appointments take place. These ask you about your child's development from birth: when they reached milestones, any regression in skills, how they communicate, how they manage social situations, sensory responses, routines, and play. This developmental history is one of the most important parts of the entire process, so it is worth setting aside proper time to complete it carefully.

The assessing team will also contact your child's school or nursery for reports. Teachers complete their own questionnaires about how your child behaves in the classroom — academically, socially, and behaviourally. Schools are asked to do this routinely as part of the referral process. It is worth letting your SENCO know the assessment is underway so they can respond promptly when contacted.

The developmental history appointment

In most NHS pathways, there is at least one appointment with a clinician where the developmental history is discussed in more depth. This is usually a face-to-face or video interview with parents or carers, without the child present. The clinician may use a structured tool such as the DISCO (Diagnostic Interview for Social and Communication Disorders) or the ADI-R (Autism Diagnostic Interview-Revised). Both are considered gold-standard tools by NICE and are used to gather a detailed picture of your child's whole developmental history, not just the presenting concerns. These are thorough interviews that can take two to three hours.

You don't need to prepare formal answers. The clinician will guide you through the questions. What does help is having thought through the details beforehand: your pregnancy and birth, early milestones, your child's first words (and any regression), how they played as a toddler, how they are in unfamiliar situations, how they respond to sensory experiences and changes to routine.

The child assessment appointment

This is the part where the clinician spends time directly with your child. For younger children this is almost always play-based, usually in a clinic room with toys and materials chosen to encourage natural interaction, communication, and imaginative play. The clinician is observing how your child initiates and responds to social contact, how they communicate, and whether any repetitive behaviours or restricted interests emerge naturally in the session.

Many NHS services and most private providers use the ADOS-2 (Autism Diagnostic Observation Schedule, Second Edition) as the structured observation tool. The National Autistic Society and NICE both describe this as a gold-standard instrument for autism diagnosis. The ADOS-2 takes around 40 to 60 minutes. It is not a pass/fail test. The clinician scores what they observe and combines that with all the other information gathered.

Tool	What it is	Who it involves
ADOS-2	Structured observation and interaction session. The clinician engages your child through play-based activities and scores what they observe in social communication and behaviour.	Child and clinician (parent usually present for younger children, in the room or just behind)
ADI-R	Semi-structured parent interview covering developmental history, communication, social behaviour and restricted/repetitive behaviours. 93 questions. Can take 2–3 hours.	Parent/carer and clinician
DISCO	Diagnostic interview that builds a whole-person picture through life history. Used more widely in the UK than the ADI-R by some services. Also covers co-occurring conditions.	Parent/carer and clinician
School/nursery reports	Standardised questionnaires completed by teachers about the child's presentation in the educational setting. Essential, as masking is often more visible at school than at home.	Teaching staff, completed in advance

The outcome appointment

After all the information has been gathered, the assessing team review everything together and reach a conclusion. This is usually shared with you in a feedback appointment, either face-to-face or by video call. You will be told the outcome and the reasoning behind it, and in most cases a written report follows within a few weeks.

The diagnostic criteria used in the UK are from the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition). An autism diagnosis is made when the clinical evidence across all the gathered information meets those criteria. The assessment team may also note co-occurring conditions at this stage, including ADHD, anxiety, or sensory processing differences.

A note on AuDHD

Autism and ADHD frequently occur together. Research suggests that between 30% and 50% of autistic children also have clinically significant ADHD, and the two conditions share several overlapping traits: difficulties with executive function, sensory sensitivities, social challenges, and emotional regulation. The term AuDHD has emerged from the neurodivergent community to describe this co-occurrence. It is not a separate formal diagnosis, but it reflects a real and common experience.

Before 2013, it was not possible to receive formal diagnoses of both autism and ADHD at the same time. That changed with the publication of the DSM-5. If you think your child may have both, it is worth saying so during the assessment process. Many clinicians will assess for both as part of the same pathway, or will recommend a further assessment if ADHD is suspected after an autism diagnosis is reached. If ADHD is your primary concern, our separate guide to ADHD assessment covers that process in detail.

How long will it all take?

This is the question most parents want answered, and the honest answer is: it depends, and it may be longer than feels reasonable.

NICE recommends that children should receive a first appointment within 13 weeks of referral. In practice, as of mid-2025, 89% of the 236,000 people with open autism referrals in England had been waiting longer than this, according to NHS Digital statistics. The National Autistic Society reported average waiting times exceeding 17 months from referral to first contact. In some areas, the average wait from referral to diagnosis is over two and a half years, according to a 2024 Children's Commissioner report on neurodevelopmental waiting times.

Waiting times vary considerably by area and by pathway. Right to Choose providers sometimes offer shorter waits, though these are affected by ICB funding arrangements and change frequently. The National Autistic Society's website publishes waiting time data updated regularly.

Private assessment: what you need to know

Some families choose a private autism assessment to avoid the NHS waiting list. This is a personal decision that depends on circumstances, urgency, and what is affordable. A few things worth knowing.

Private autism assessments in the UK typically cost between £1,500 and £3,500 for a child, depending on the provider, the tools used, and the level of involvement from the assessing team. A good private assessment should use the same NICE-recognised tools as an NHS assessment: the ADOS-2 and either the ADI-R or DISCO for the developmental history. A reputable provider will have CQC-registered clinicians and provide a comprehensive written report.

A private diagnosis is generally accepted by schools and local authorities when applying for an EHCP, though they are not obligated to act on it without further assessment of their own. If your child is also being considered for ADHD medication, the prescribing situation with private diagnosis is more complex — our ADHD medication guide covers the shared care arrangement in more detail.

Some health insurance policies cover private autism assessments. It is worth checking your policy documents carefully. Some national charities also have small grant funds for families who cannot afford a private assessment, though these are competitive and eligibility varies.

What happens after a diagnosis

A diagnosis is not the end of the process. It is the point at which a clearer path forward becomes possible.

What to do while you wait

The waiting period can be one of the most difficult parts for families, particularly when your child is visibly struggling. Here are some things that can make a real difference in the meantime.

• Talk to the SENCO. You don't need a diagnosis for the school to start SEN Support. Request a meeting and ask what adjustments can be made now. This might include movement breaks, a quiet space, visual timetables, or sensory diet strategies recommended by the school OT.
• Keep a diary. Note specific incidents, triggers, and how long they last. This information will be useful during the assessment itself, and it helps you track patterns.
• Look into sensory support. If sensory processing differences are part of what you're seeing, practical adjustments at home and school can help significantly, even before a formal diagnosis. Ear defenders for noisy environments, weighted lap pads for focus, or a calm-down tent at home are the kinds of tools many families find useful in the waiting period.
• Connect with other parents. The National Autistic Society (autism.org.uk) has a community forum. Local SEND parent support groups often have people who have been through the same process in your area and can tell you what the local service is like in practice.
• Look after yourself. This process is stressful. After-school meltdowns, uncertainty about the outcome, fighting for support at school — it adds up. You are allowed to find it hard.

Useful resources

• National Autistic Society — autism.org.uk The most comprehensive UK resource for autism information, including detailed guidance on the assessment process, your rights, and what to do if your referral is refused. Their helpline is 0808 800 4104.
• NHS — nhs.uk/conditions/autism The NHS website explains the referral process and what to expect in plain language. A good first stop for understanding the standard NHS pathway.
• NICE Guideline NG142 — Autism: recognition, referral, diagnosis and management The full NICE clinical guideline that NHS services are expected to follow. The patient section is accessible and useful for understanding what standards NHS assessments should meet.
• Children's Commissioner for England — childrenscommissioner.gov.uk Their 2024 report on neurodevelopmental waiting times is the most thorough recent overview of how long families are waiting across England.
• Ambitious About Autism — ambitiousaboutautism.org.uk Practical advice and resources for families, including a toolbox of strategies for supporting autistic children while waiting for a diagnosis.