What happens at a child's autism assessment?

At an autism assessment, a team of professionals takes your child's history, interviews you, and watches them play and interact, usually over one or more visits, before deciding whether your child is autistic.

It is not a single test your child sits and either passes or fails. There is no blood test and no quiz with a score at the end. The team builds a picture of your child's whole development, and the outcome may be autism, autism alongside another condition, or no diagnosis at all.

What the assessment involves, step by step

1. Gathering information before the appointment. The team reads the referral, sends you and often your child's nursery or school questionnaires about how they communicate, play and cope day to day, and reviews relevant medical records.
2. A developmental interview with you. A clinician asks in detail about your child's early development, language, play, friendships and behaviour, from the earliest years to now. You know your child best, so this account carries real weight.
3. A direct observation of your child. A professional spends time with your child through play and structured activities, often using a tool such as the ADOS-2, watching how they communicate and interact. You are usually in or near the room, and this part typically lasts around one and a half to two hours.
4. Checks for other conditions. The team may do a brief physical examination and screen for things that often sit alongside autism, such as ADHD, language difficulties or sensory differences. In some areas they also observe your child in school.
5. The team decides together. The professionals meet, weigh the history, the observation and the school information, and reach a clinical judgement about whether your child meets the criteria for autism.

Per NICE guidance, this work is done by a multidisciplinary team, usually including a paediatrician or child psychiatrist, a speech and language therapist and a psychologist, rather than one clinician. NICE is also clear that no single autism tool can be relied on on its own to make the diagnosis. The NHS and the National Autistic Society describe the same shape: history, observation and information from across settings, brought together by a team.

The feedback and the written report

After the team has decided, you are usually offered a feedback appointment where the outcome is explained in person, followed by a written report. The report sets out what the team found, whether it is autism, your child's strengths, the areas where they need support and any other conditions picked up. With your consent it is shared with your GP and your child's school, and it may come with a follow-up appointment or a plan for the support needed.

How long it takes to reach this point

NICE recommends the assessment should start within three months of the referral reaching the autism team. In practice the wait is far longer. As of March 2026, around 270,000 people in England had an open referral for suspected autism, and roughly nine in ten had already waited beyond the 13 weeks NICE recommends (NHS England Digital). So the appointment you are preparing for has usually followed a wait of many months to several years. If your child is being looked at for ADHD too, our sibling answer on whether autism and ADHD can be assessed at the same time explains how that works, and how a GP referral is made covers getting onto the pathway in the first place.

This page is general information, not clinical or legal advice.