If your child has been referred for an autism assessment, you may feel unsure about what will happen or what the specialists will be looking for. The assessment is designed to understand your child’s development, social communication, behaviour, strengths and everyday needs rather than judge them from one particular behaviour or one appointment.
Your child’s assessment should bring together information from you, your child and other relevant sources such as their school or nursery. Specialists use this information alongside direct interaction and observation to consider whether your child’s developmental profile meets recognised diagnostic criteria for autism and whether another or coexisting condition also needs attention.
What Is an Autism Assessment?
An autism assessment is a comprehensive evaluation used to determine whether your child’s developmental profile meets recognised diagnostic criteria for autism. It considers social communication and interaction, behaviour and interests, sensory experiences, developmental history and the effect of your child’s differences on everyday life.
The assessment should also build a profile of your child’s strengths, skills and support needs. This means the process should provide useful information about your child even when the eventual conclusion is that they do not meet the diagnostic criteria for autism.
Who Carries Out an Autism Assessment?
Your child’s autism assessment should involve professionals with appropriate training and experience in autism. NICE recommends a specialist autism team whose core membership for children and young people includes a paediatrician and/or child and adolescent psychiatrist, a speech and language therapist and a psychologist experienced in working with autistic children and young people.
Depending on your child’s individual needs, the team may also involve or have access to professionals such as an occupational therapist, specialist nurse, specialist teacher, paediatric neurologist or social worker. The exact professionals you meet can therefore vary between services.
Will You Have a Main Contact During the Assessment?
NICE recommends that every child or young person undergoing an autism diagnostic assessment has a case coordinator within the autism team. This person should act as a main point of contact for you and, when appropriate, your child while the assessment is taking place.
Your coordinator should help keep you informed about the likely sequence and timing of different parts of the assessment and help gather relevant information for the team. Individual services may use a different job title for this role.
What Happens at the Initial Consultation?
During the initial consultation, your specialist will usually discuss the concerns that led to your child’s assessment and ask how they manage in everyday situations. You may discuss communication, social interaction, behaviour, interests, routines, sensory experiences, home life and education.
When appropriate for your child’s age and understanding, the team should also consider their own concerns and experiences. This first discussion helps the specialists understand what you and your child have noticed and which areas need to be explored in greater detail during the assessment.
Why Is Developmental History Important?
You will usually be asked detailed questions about your child’s development from early childhood onwards. This may include early communication, movement, play, social development, behaviour and when developmental milestones were reached.
Your specialist will look for developmental and behavioural patterns relevant to recognised autism diagnostic criteria rather than focusing only on how your child behaves today. Understanding their developmental history also helps the team consider whether another developmental condition could better explain some of their difficulties.
Will Medical History Be Discussed?
Yes. Your child’s assessment should include their medical history, including relevant pregnancy and birth history, family history and past and current health conditions. Previous medical investigations, hearing or vision information and other relevant assessments may also be reviewed.
NICE also recommends a physical examination as part of the autism diagnostic assessment. The purpose is not to physically test whether your child is autistic, but to identify medical or developmental findings that may need further attention or help the team understand your child’s overall health and development.
How Is Your Child’s Communication Assessed?
Your specialist will consider how your child communicates with other people through spoken language, gestures, facial expression and other forms of communication relevant to them. They may look at how your child starts or responds to interaction, shares interests, manages back-and-forth communication and understands social situations.
Communication should be considered as part of your child’s wider social and developmental profile rather than judged from one skill such as eye contact or speech. Your child’s communication style may also vary depending on the person, activity and environment.
Will the Specialist Observe Your Child?
Observation is an important part of an autism diagnostic assessment because it allows specialists to directly consider your child’s social communication, interaction and behaviour. The way this happens should be appropriate for your child’s developmental level, communication abilities and age.
Your child’s behaviour during one clinical appointment should not be considered in isolation. If what the team observes differs substantially from information provided by you, school or nursery, NICE recommends gathering additional information or considering observations in another setting.
What Might Structured Activities Look Like?
Structured activities during an autism assessment are adapted to your child’s age and communication style and may include toys, games, pictures, conversations or interactive tasks. They allow your specialist to observe social communication, interaction, play and behaviour alongside information from your child’s developmental history and everyday experiences.
Structured Activities During an Autism Assessment
| Activity | Who May Take Part | What It May Assess | Why It Matters |
| Toys and play | Younger children | Play skills and social interaction | Shows how your child naturally engages with others |
| Games | Younger children and school-age children | Turn-taking, flexibility and interaction | Provides opportunities to observe social responses |
| Pictures | Children with different communication abilities | Communication and understanding | Helps explore how your child responds to visual information |
| Interactive activities | Children across different ages | Reciprocal interaction and social communication | Shows how your child responds during shared activities |
| Conversation | Older or more verbally able children | Conversational style and social communication | Helps assess how your child maintains interaction |
| Structured tasks | Children depending on their age and needs | Flexibility and patterns of behaviour | Provides consistent opportunities for observation |
| Everyday information | All children | Development and behaviour outside the assessment | Helps place observations within your child’s wider experiences |
Are Questionnaires Used During an Autism Assessment?
You, your child when appropriate, or people who know them well may be asked to complete questionnaires or structured forms about development, communication, behaviour, sensory experiences and everyday functioning. The exact questionnaires used vary between services.
These tools can help organise information, but your child’s diagnosis should never be based on a questionnaire score alone. NICE advises that tools may support information gathering but should not be used independently to confirm or rule out autism.
Why Is Information From School or Nursery Important?
School or nursery information can show how your child communicates, learns, manages routines and interacts with others outside the home. It gives the assessment team another view of your child’s strengths and difficulties.
- Learning: Shows how your child manages classroom tasks and learning.
- Social interaction: Describes how your child interacts with peers and adults.
- Communication: Provides information about how your child communicates in daily situations.
- Routines: Shows how your child responds to structure and changes.
- Different settings: Helps explain differences between behaviour at home and school.
Your child may behave differently across settings, and this does not mean one account is incorrect. The assessment team can explore these differences and seek further information when needed.
What If Home and School See Different Things?
You may describe significant difficulties at home while your child’s school reports fewer concerns, or the opposite may happen. Differences can occur because environments vary in structure, sensory demands, social expectations and the amount of support your child receives.
A disagreement between reports does not automatically confirm or rule out autism. NICE recommends gathering additional information or carrying out further autism-specific observations in other settings when reported characteristics and clinical observations do not match.
Is There a Single Test for Autism?
No. There is no single questionnaire, observation, blood test, scan or structured autism tool that can independently determine whether your child is autistic. The diagnosis is based on information gathered from multiple sources together with specialist clinical judgement.
Your team should consider your child’s developmental history, direct assessment, information from relevant settings and recognised diagnostic criteria. NICE specifically advises clinicians not to rely on any autism-specific diagnostic tool alone.
Are Tools Such as ADOS Always Used?
No. Some services use structured tools such as the Autism Diagnostic Observation Schedule, or ADOS, to gather additional information about your child’s social communication, interaction and behaviour. Other services may use different structured tools or approaches depending on your child’s needs and their local assessment pathway.
An ADOS result cannot diagnose or rule out autism by itself. NICE advises that no autism-specific diagnostic tool should be relied on alone, and a 2025 systematic review similarly concluded that structured diagnostic tools should complement rather than replace clinical judgement.
Do Specialists Look for Other Conditions?
Yes. Your child’s autism assessment should consider whether another condition could explain some of their difficulties and whether another developmental, mental-health or physical-health condition occurs alongside autism.
Depending on your child’s individual profile, the team may consider ADHD, anxiety, mood difficulties, speech or language disorders, learning difficulties, developmental coordination difficulties, tics, epilepsy, sleep problems, feeding difficulties and hearing or vision problems. Appropriate further assessment or referral can then be arranged when needed.
How Do Specialists Decide Whether Your Child Is Autistic?
Your assessment team brings together information from your child’s developmental and medical history, direct interaction and observation, information from home and education and any relevant structured assessment tools. They then consider the complete pattern using recognised diagnostic criteria such as ICD-11 or DSM-5.
The decision should be based on information from all relevant sources together with specialist clinical judgement. One appointment, ADOS result, questionnaire score or particular behaviour should not independently determine the outcome.
What Happens After the Assessment?
After the assessment, the team should explain their findings and the reasons for their conclusion to you and, when appropriate, your child. You should receive a written report describing the assessment findings, whether your child meets the diagnostic criteria for autism, the reasons for the conclusion and their individual strengths, difficulties and support needs.
If your child is diagnosed as autistic, NICE recommends offering a follow-up appointment with an appropriate member of the autism team within six weeks of the end of the assessment. If the diagnosis remains uncertain, your child may be kept under review or a second opinion may be considered. If autism is not diagnosed, the team should still consider appropriate support, referral or further assessment based on your child’s individual profile.
Where Can You Arrange a Specialist Autism Assessment?
If you have ongoing concerns about your child’s communication, interaction, behaviour or development, arranging a specialist autism assessment for children in London can help you explore their developmental profile in greater detail.
A comprehensive assessment can help clarify whether your child’s characteristics meet recognised diagnostic criteria for autism, whether another or coexisting condition should be considered and which educational, developmental or healthcare support may be appropriate.
Myth vs Fact
| Myth | What You Should Know |
| Your child can be diagnosed from one appointment. | Your child’s team should consider developmental history, observation and information from different sources. |
| Your child must show obvious autistic characteristics during the appointment. | Your child’s behaviour in one clinical setting is only one part of the wider assessment. |
| ADOS can tell you definitively whether your child is autistic. | Your child’s ADOS result can provide useful information but cannot diagnose or exclude autism by itself. |
| A questionnaire can diagnose your child. | Your child’s questionnaire results must be interpreted within the comprehensive clinical assessment. |
| School must see exactly the same behaviours that you see at home. | Your child’s presentation may differ between environments, and discrepancies should be explored rather than dismissed. |
| Your child needs a brain scan to diagnose autism. | Your child’s diagnosis is usually based on developmental and clinical assessment, not routine neuroimaging. |
| Every autistic child needs genetic testing. | Your child should have genetic testing only when their individual clinical profile provides an appropriate reason. |
| The assessment only looks for autism. | Your child’s team should also consider alternative and coexisting developmental, mental-health and physical-health conditions. |
| The assessment only focuses on your child’s difficulties. | Your child’s strengths, skills and support needs should also be documented. |
| If autism is not diagnosed, the assessment has failed. | Your child’s assessment can still identify important needs and guide further support or assessment. |
Key Takeaways
- Your child cannot be diagnosed with autism from one behaviour, questionnaire or observation.
- Your child’s assessment should consider their developmental and medical history.
- Your child’s own experiences and concerns should be included when appropriate for their age and understanding.
- Your child should be observed interacting and communicating as part of the assessment.
- Your child’s school or nursery may provide important information, but their presentation does not need to look identical in every setting.
- Your child may take part in structured autism-specific activities, but tools such as ADOS are not required in every assessment.
- Your child’s ADOS or questionnaire result cannot establish an autism diagnosis by itself.
- Your child’s physical health and possible coexisting developmental or mental-health conditions should also be considered.
- Your child does not routinely need blood tests, brain scans or genetic testing simply to diagnose autism.
- Whatever the diagnostic outcome, you should receive an explanation of the findings and your child’s strengths and support needs.
UK Guidance Note
NICE recommends that your child’s autism diagnostic assessment is carried out through a specialist autism team and includes a developmental history, direct assessment of social communication and behaviour, medical history, physical examination, consideration of alternative and coexisting conditions and a profile of your child’s strengths and needs.
NICE’s quality standard says that diagnostic assessment should start within three months of referral to an autism team, although the NHS notes that actual waiting times can be several months or longer depending on local services. Structured autism tools can contribute to the process but should never be used independently to make or rule out your child’s diagnosis.
Frequently Asked Questions
1. How long will your child’s autism assessment take?
Your child’s assessment may involve one or more appointments depending on their developmental profile and the information the team needs. Different professionals may contribute at different stages, so there is no single duration that applies to every child.
2. What happens during your child’s first autism assessment appointment?
Your specialist will usually discuss your concerns and ask about your child’s development, communication, social interaction, behaviour, interests, routines, sensory experiences, medical history and everyday life. Your child’s own experiences should also be considered when appropriate.
3. Will your child be observed during the autism assessment?
Yes. Direct interaction and observation form part of the diagnostic assessment. Your specialist considers your child’s social communication and behaviour alongside developmental history and information from other relevant settings rather than relying on the observation alone.
4. Will your child need ADOS?
Not necessarily. Some services use ADOS or another autism-specific structured tool, while others may use different assessment methods. NICE states that no autism-specific diagnostic tool should be relied on alone.
5. Will your child’s school or nursery be involved?
Your child’s school or nursery will usually be an important source of information about communication, learning, relationships and behaviour outside the home. If school and home reports differ, the team can gather further information or observations rather than assuming that autism has been ruled out.
6. Will your child need blood tests, genetic tests or a brain scan?
Not routinely. Your child’s autism diagnosis is based on developmental and clinical assessment. NICE recommends considering genetic testing in particular clinical circumstances and an EEG when epilepsy is suspected.
7. Does your child’s assessment look for ADHD and other conditions?
Yes. Your specialist should consider alternative and coexisting conditions such as ADHD, anxiety, language or learning difficulties, developmental coordination difficulties, epilepsy, sleep problems and hearing or vision difficulties according to your child’s individual needs.
8. How does the team decide whether your child is autistic?
Your specialist team uses information from all relevant sources together with clinical judgement and recognised diagnostic criteria. Your child’s diagnosis should not depend on one behaviour, questionnaire or structured assessment result.
9. What happens if your child is diagnosed as autistic?
The team should explain the diagnosis and provide you with a written report describing the assessment findings, your child’s strengths and their support needs. NICE recommends offering a follow-up appointment with an appropriate team member within six weeks after the assessment.
10. What happens if your child is not diagnosed with autism?
Your child’s assessment can still identify important strengths, difficulties or other possible conditions. The team should explain why the autism criteria were not met and consider appropriate services, further assessment or review based on your child’s individual profile.
Final Thoughts: Understanding What Happens During an Autism Assessment
If you are considering an autism assessment for your child, knowing what to expect can make the process feel less uncertain. A comprehensive assessment looks beyond one behaviour or appointment, bringing together your child’s developmental history, communication, social interaction, observations and information from home and school.
Whether or not your child receives an autism diagnosis, the assessment can help you understand their individual strengths, difficulties and support needs. If you’re considering autism assessment for children, you can get in touch with us at London Paediatric Clinic.
References:
- National Institute for Health and Care Excellence (2011, updated 2017) Autism spectrum disorder in under 19s: recognition, referral and diagnosis. NICE guideline CG128. Available at: https://www.nice.org.uk/guidance/cg128/
- National Institute for Health and Care Excellence (2014, updated 2023) Autism. NICE quality standard QS51. Available at: https://www.nice.org.uk/guidance/qs51/
- NHS (2026) ‘Autism assessments’. Page last reviewed 6 May 2026. Available at: https://www.nhs.uk/conditions/autism/assessments/
- NHS (2026) ‘Signs of autism in children’. Page last reviewed 6 May 2026. Available at: https://www.nhs.uk/conditions/autism/signs-in-children/
- Leicestershire Partnership NHS Trust (no date) ‘Autism assessment for a child aged 2–12’. Available at: https://www.leicspart.nhs.uk/autism-space/assessment-diagnosis/autism-assessment-process-for-a-child-aged-2-12-what-to-expect/
- Brian, J.A., Zwaigenbaum, L. and Ip, A. (2019) ‘Standards of diagnostic assessment for autism spectrum disorder’, Paediatrics & Child Health, 24(7), pp. 444–451. Available at: https://academic.oup.com/pch/article/24/7/444/5603338
- Lebersfeld, J.B., Swanson, M., Clesi, C.D. and O’Kelley, S.E. (2021) ‘Systematic review and meta-analysis of the clinical utility of the ADOS-2 and the ADI-R in diagnosing autism spectrum disorders in children’, Journal of Autism and Developmental Disorders, 51(11), pp. 4101–4114. Available at: https://pubmed.ncbi.nlm.nih.gov/33475930/
- Barbaresi, W. et al. (2022) ‘Clinician diagnostic certainty and the role of the Autism Diagnostic Observation Schedule in autism spectrum disorder diagnosis in young children’, JAMA Pediatrics, 176(12), pp. 1233–1241. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9577880/
- Fulceri, F. et al. (2025) ‘Autism diagnosis in children and adolescents: A systematic review and meta-analysis of test accuracy’, Neuroscience & Biobehavioral Reviews, 173, article 106164. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0149763425001642