A paediatric autism assessment in the UK is a multi-disciplinary process built on NICE guideline CG128, which sets out how children and young people under 19 should be assessed and diagnosed [1]. The detail varies by service, but the underlying shape is consistent. This article covers what to expect, the tools clinicians use, what to bring, and what the report contains.
Who does the assessment
NICE recommends that autism assessment in children is carried out by a multi-disciplinary team with appropriate training [1, 2]. In NHS community paediatric services, the team usually involves:
- A community paediatrician or a child and adolescent psychiatrist
- A specialist nurse, psychologist or learning disability nurse
- A speech and language therapist
- An occupational therapist, where sensory and motor difficulties are part of the picture
- Input from school and from parents
In private services such as NeuroFX, the same NICE-aligned multi-disciplinary framework applies. The team may be smaller, but the components (developmental history, structured observation, information from school) are the same.
A single individual clinician carrying out a one-hour observation and producing a same-day diagnosis is not consistent with NICE; the assessment is a process, not a single appointment.
The components of a NICE-aligned assessment
A NICE-aligned paediatric autism assessment normally includes [1, 2]:
A developmental history with parents
A detailed conversation, often two to three hours, covering your child from infancy onwards. The structured tool most commonly used is the Autism Diagnostic Interview-Revised (ADI-R) [5]. The ADI-R covers early development, language, social behaviour, play, restricted and repetitive behaviours, and current functioning. Even where the full ADI-R is not used, a developmental history of similar depth is standard.
The history is the single most important component of the assessment. Memory is fallible; the things that felt unremarkable at the time often turn out to be diagnostic. Most parents underestimate how much they will be asked to recall.
A structured observation of the child
The most widely used observational tool is the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) [4]. The ADOS-2 has several modules matched to age and language level. The session involves the clinician offering structured tasks and conversation that create opportunities for the child to show social communication, play, imagination, conversation and restricted or repetitive interests. It usually takes about 45 minutes to an hour.
The ADOS-2 is not a pass-or-fail test. A child who scores above threshold is not automatically diagnosed; a child who scores below threshold is not automatically ruled out. The clinician integrates the ADOS-2 with everything else.
Where the ADOS-2 is not used, a structured clinical observation of equivalent depth is standard.
Information from school
The assessment team will request input from school, either via questionnaire, letter, or a phone call with the class teacher or SENCo. The school perspective often differs from the home perspective in revealing ways. Where school information is missing, the assessment is incomplete.
Cognitive, language and other assessments where indicated
Depending on the picture, additional assessments may form part of the work-up. Cognitive testing where learning difficulty is a question. Language assessment where communication is unusual. Occupational therapy input where sensory or motor difficulties are part of the presentation.
A formulation
The team integrates the history, observation, school information and any additional testing into a diagnostic formulation: a clinical judgement about whether the picture meets DSM-5-TR or ICD-11 criteria for autism, what co-occurring difficulties are present, and what support is recommended [3]. The formulation, not any single tool, is the diagnosis.
What to bring
For the developmental history appointment, the following are helpful [1, 7]:
- The red book or any earlier health visitor records, where available
- School reports from the earliest years through to the current year
- Any previous reports (speech and language, occupational therapy, educational psychology)
- A timeline of any concerns that have been raised, by you or by others
- Any previous referrals or assessments and their outcomes
- A note of what your child was like as a baby and toddler: eye contact, response to name, language milestones, play, sleep, feeding
- Examples of patterns rather than one-off events; specific incidents that feel typical
- For older children and adolescents, your child's own perspective in whatever form suits them
A short written summary (one or two pages) of your concerns, what you have noticed, and the questions you have, is genuinely useful to the clinician. Many parents find writing this also helps clarify their own thinking before the appointment.
What the day looks like for your child
For most children, the observation appointment is the part that involves them. It is intended to feel like structured play and conversation, not a test. The clinician will be friendly, the room will usually be a clinical space rather than a play centre, and the activities are designed to fit the child's age and language level.
A few practical points worth knowing [7]:
- Most children, including autistic children, can sustain the observation appointment. It is designed to be doable.
- Some autistic children mask hard in clinical settings; this is real and the experienced clinician knows to look for it.
- It is fine to tell your child this is an appointment with a doctor (or psychologist) who wants to get to know how their mind works.
- Your child does not need to perform a particular way. The clinician is observing how they respond to the structured tasks, not whether they get the tasks right.
What the report contains
A NICE-aligned paediatric autism assessment report normally contains [1, 2]:
- A summary of the developmental history
- A summary of the structured observation findings (and any tools used, with scores where relevant)
- Information from school
- Results of any cognitive, language or occupational therapy assessments
- A clinical formulation, with reference to DSM-5-TR or ICD-11 criteria
- A diagnostic conclusion (autism present, autism not present, or further information required)
- Co-occurring conditions identified or recommended for further assessment (ADHD is particularly common alongside autism)
- Recommendations for support at home, at school, and through health services
The report should be detailed enough to be useful to school, to other clinicians, and to the family. A report that is two pages with a one-line conclusion is not consistent with NICE.
What happens after the report
A diagnosis is the gateway, not the endpoint. After diagnosis:
- The school can use the report to update SEN Support or to support an EHC needs assessment, covered in detail in our piece on school support for autism.
- Your local authority's autism support pathways and parent training programmes become accessible.
- Co-occurring conditions identified in the report (ADHD, anxiety, sleep difficulty, sensory processing difficulty) often warrant their own next steps.
- Many parents find that the diagnosis changes how they understand their child, not just how the system responds. That shift takes time.
NHS waiting times for paediatric autism assessment are often substantial, two years or more in many areas. Where this is not workable, NeuroFX offers private autism assessment for children aged 6 and upwards with the same NICE-aligned framework. Where ADHD is also being considered, combined ADHD and autism assessment in Bedford avoids running two assessments back to back.
What this means in practice
- A paediatric autism assessment is a multi-disciplinary process built on NICE CG128: a developmental history, a structured observation, information from school, and a clinical formulation. No single tool is diagnostic.
- The ADI-R and the ADOS-2 are the most widely used tools. Either is normal; equivalent structured alternatives are also used.
- The developmental history is the most important part. Bring school reports, earlier records, examples of patterns, and any previous assessments.
- The observation appointment is designed to be doable for the child. It is structured play and conversation rather than a test.
- The report should be detailed enough to be useful to school and to other clinicians. A two-page report with a one-line conclusion is not consistent with NICE.
When to speak to a professional
Speak to your GP to request an NHS paediatric autism referral. Speak to the school SENCo at the same time; school information forms part of the assessment. Where NHS waits are not workable, private autism and ADHD assessment for adults and children aged 6 and upwards is a legitimate parallel route. Seek urgent help via 111, 999 or A&E for any acute mental health crisis or significant safety concern.
Sources
- NICE. Autism spectrum disorder in under 19s: recognition, referral and diagnosis. CG128. National Institute for Health and Care Excellence. https://www.nice.org.uk/guidance/cg128
- NICE. Autism spectrum disorder in under 19s: support and management. CG170. National Institute for Health and Care Excellence. https://www.nice.org.uk/guidance/cg170
- American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). Washington, DC: American Psychiatric Association; 2022.
- Lord C, Rutter M, DiLavore PC, et al. Autism Diagnostic Observation Schedule, Second Edition (ADOS-2). Torrance, CA: Western Psychological Services; 2012.
- Rutter M, Le Couteur A, Lord C. Autism Diagnostic Interview-Revised (ADI-R). Torrance, CA: Western Psychological Services; 2003.
- Royal College of Psychiatrists. Autism assessment guidance. https://www.rcpsych.ac.uk/
- National Autistic Society. Getting a diagnosis. https://www.autism.org.uk/
