Autism and developmental screening: when it is done and what the scores mean
Developmental surveillance and screening aim to find conditions that affect a young child's development early. Autism screening helps find out whether a child has early signs that could be autism spectrum disorder (ASD), but it cannot diagnose it. (AAP, 2020 development report) (MedlinePlus, ASD screening) Symptoms usually show up in the first two years of life. (MedlinePlus, ASD screening)
When it is done
The American Academy of Pediatrics (AAP) Bright Futures schedule lists these checks: (AAP Bright Futures, 2025)
| Visit | What is done |
|---|---|
| Every well-child visit | Developmental surveillance: the clinician asks about and watches the child's development. (AAP, 2020 development report) (AAP Bright Futures, 2025) |
| 9 months | Standardized developmental screening test. (AAP, 2020 development report) (AAP Bright Futures, 2025) |
| 18 months | Standardized developmental screening test and autism screening. (AAP, 2020 development report) (AAP, 2020 autism report) (AAP Bright Futures, 2025) |
| 24 months | Autism screening. (AAP, 2020 autism report) (AAP Bright Futures, 2025) |
| 30 months | Standardized developmental screening test. (AAP, 2020 development report) (AAP Bright Futures, 2025) |
| 4 to 5 years | Special attention to surveillance before school entry, with screening if there are any concerns. (AAP, 2020 development report) |
Developmental concerns raised at any visit should be followed by a standardized screening test or a direct referral to intervention and specialty care. (AAP, 2020 development report) The conditions this screening aims to find include autism, deafness or being hard of hearing, intellectual and motor disabilities, and behavioral conditions. (AAP, 2020 development report)
Older children and adults may also be screened if they have signs of autism and were never diagnosed. (MedlinePlus, ASD screening)
How screening is done
- Questionnaires: you usually fill in one or more questionnaires about your child's development and behavior, including speech, movement, thinking and emotions. You may also be asked about your family health history. (MedlinePlus, ASD screening)
- The M-CHAT-R/F: the most studied autism screening tool for this age group. (USPSTF, 2016) Parents first answer 20 yes or no questions, which takes under 5 minutes. If the child screens positive, the parents are asked structured follow-up questions. It is free for clinical use. (Robins, 2014)
- What it looks at: communication skills, joint attention, repetitive movement and pretend play. (USPSTF, 2016)
What M-CHAT-R/F scores mean
The total score on the first questionnaire puts a child in one of three risk ranges. (Robins, 2014)
| Total score | Risk range | What it leads to |
|---|---|---|
| 0 to 2 | Low risk | No follow-up or further evaluation unless surveillance shows autism risk. A child younger than 24 months should be screened again, as the AAP recommends. (Robins, 2014) |
| 3 to 7 | Medium risk | The follow-up interview is done to ask more about the items that scored. About one-third of children whose parents complete it still show risk and need referral for evaluation and possible early intervention. (Robins, 2014) |
| 8 to 20 | High risk | The follow-up may be skipped. In the study, every child in this range who was evaluated had a developmental delay or concern, which justified immediate referral for evaluation and possible early intervention. (Robins, 2014) |
In the 2014 validation study of 16,071 toddlers, children who scored 3 or more on the questionnaire and 2 or more after the follow-up had a 47.5% chance of being diagnosed with autism and a 94.6% chance of some developmental delay or concern. (Robins, 2014) The USPSTF found that the M-CHAT tools had a positive predictive value of about 50% for autism in unselected US children aged 16 to 30 months. (USPSTF, 2016) Many children with autism score lower than the high-risk cut-off, so the follow-up matters for medium-risk scores. (Robins, 2014)
Language milestones that call for more tests
MedlinePlus says more tests may be needed if a child does not meet any one of these: (MedlinePlus, ASD)
- Babbling by 12 months
- Gesturing (pointing, waving bye-bye) by 12 months
- Saying single words by 16 months
- Saying two-word spontaneous phrases by 24 months (not just echoing)
- Losing any language or social skills at any age
These children might need a hearing test, a blood lead test and a screening test for autism. (MedlinePlus, ASD) NICE says children younger than 3 with regression in language or social skills should be referred to the autism team. (NICE CG128) Signs the NHS lists in young children include not responding to their name, using eye contact less often and not taking part in pretend play. (NHS, signs in children)
Screening vs a diagnostic evaluation
- Screening finds children who may need a closer look. It cannot diagnose autism. (MedlinePlus, ASD screening) NICE says a positive score may support a decision to refer but can be for reasons other than autism, and a negative score does not rule autism out. (NICE CG128)
- A diagnostic evaluation is done by a specialist. There is no one test that can diagnose autism, so the specialist uses a combination of methods, including detailed questionnaires or interviews with parents, teachers or caregivers. (MedlinePlus, ASD screening) An NHS assessment team may ask about your child's development and medical history, do a physical exam, see how your child plays and interacts with you, and read reports from their GP, nursery or school. (NHS, autism assessments)
Early intervention referral
In the US, federal rules have each state run a statewide early intervention system for infants and toddlers with disabilities, known as the Part C program. (34 CFR 303)
- Who qualifies: a child under 3 who has a developmental delay in cognitive, physical (including vision and hearing), communication, social or emotional, or adaptive development, or a diagnosed condition with a high probability of causing delay. (34 CFR 303)
- Who can refer: referral sources include physicians, hospitals, child care programs and parents. A referral is to be made as soon as possible, and no more than seven days after a child has been identified. (34 CFR 303)
- Timeline: the initial evaluation, assessments and first plan meeting must be completed within 45 days of the referral, with exceptions for family circumstances or missing consent. (34 CFR 303)
- Cost: evaluation and assessment are done at public expense, with no fees to parents. (34 CFR 303)
In England, a GP can often refer a child to a local autism team. If the child is not school age, a health visitor may need to make the referral. (NHS, autism assessments)
Where they differ:
- AAP: standardized autism screening for all children at 18 and 24 months, (AAP, 2020 autism report) and developmental screening tests at 9, 18 and 30 months. (AAP, 2020 development report)
- USPSTF: too little evidence to weigh benefits and harms of autism screening in children 18 to 30 months with no concerns raised (I statement, 2016). It is not a recommendation for or against, and clinicians should listen carefully to parents' concerns. (USPSTF, 2016) An update is in progress. (USPSTF, update in progress)
- NHS: health visitor reviews at 9 to 12 months and at 2 to 2 and a half years, with the Ages and Stages Questionnaire (ASQ-3) filled in before each. The 9 to 12 month review covers general development, including movement, speech, social skills and behavior. (NHS, development reviews) NICE says tools to identify an increased likelihood of autism may help gather information but are not essential. (NICE CG128)
Your doctor decides what your result means for you.
This page does not give therapy or treatment advice. If a screening was flagged, see after an abnormal screening result for questions to ask.
Questions people ask
At what ages are toddlers screened for autism?
The American Academy of Pediatrics recommends standardized autism screening at the 18 and 24 month well-child visits, along with developmental surveillance at every visit. (AAP, 2020 autism report) (MedlinePlus, ASD screening)
What does a medium-risk M-CHAT-R/F score mean?
A total of 3 to 7 is medium risk. It means the follow-up interview should be done to learn more about the items that scored. In the validation study, about one-third of children whose parents completed the follow-up still showed risk and needed referral for evaluation. (Robins, 2014)
Does a positive screening mean my child has autism?
No. Screening cannot diagnose autism. If a screening shows a child may have it, more testing is needed to find out. There is no one test that can diagnose autism, so a specialist uses a combination of methods. (MedlinePlus, ASD screening)
Can a negative screening rule out autism?
No. NICE says a negative score on a tool to identify an increased likelihood of autism does not rule it out. MedlinePlus notes that screening may not find milder cases in early childhood. (NICE CG128) (MedlinePlus, ASD screening)
Does the USPSTF recommend autism screening?
The USPSTF found too little evidence to weigh the benefits and harms of screening children aged 18 to 30 months when no concerns have been raised (I statement, 2016). It says this is not a recommendation for or against screening. An update is in progress. (USPSTF, 2016) (USPSTF, update in progress)