M-CHAT Autism Screening: What Parents Need to Know

M-CHAT autism screening is a short parent questionnaire that checks whether a toddler aged 16 to 30 months has a higher likelihood of autism. Its full name is the M-CHAT-R/F. It is quick, free, and used at 18- and 24-month checkups. It is a screen, not a diagnosis: a positive result means a closer look is needed [1][2].

What is M-CHAT autism screening?

The Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F) was developed by Diana Robins, Deborah Fein, and Marianne Barton. It is a two-stage tool [1]:

1. Stage 1: the questionnaire. Parents answer 20 yes/no questions about everyday behaviors, such as whether their child points to show things, responds to their name, or brings things to show them.
2. Stage 2: the Follow-Up. If the first score is in the middle range, a clinician asks structured follow-up questions about the items that scored, with real examples from your child’s life.

The authors’ instructions say it is validated for toddlers between 16 and 30 months, and that studies have used it up to 48 months [1]. It was designed to catch as many autistic children as possible, which means it also flags some children who are not autistic. That is why the follow-up step exists.

The M-CHAT-R/F is free to download for clinical, research, and education use, but it is copyrighted and must not be changed or reposted without permission [1]. That is why this guide links to the official site rather than reproducing the questions.

When is M-CHAT autism screening done?

The American Academy of Pediatrics (AAP) recommends formal autism screening for every child at the 18- and 24-month well-child visits, along with developmental monitoring at every visit and general developmental screening at 9, 18, and 30 months [3][4]. Screening should also be done any time a parent raises a concern [2].

The AAP does not endorse a single tool, but the M-CHAT-R/F is the most commonly used autism screener in pediatric offices. Others include the Ages and Stages Questionnaires: Social-Emotional (ASQ:SE-2), the Communication and Symbolic Behavior Scales (CSBS), and the Parent’s Observations of Social Interactions (POSI) [2][5].

What do other guidelines say?

The US Preventive Services Task Force (USPSTF) concluded in 2016 that there was not enough evidence to judge the balance of benefits and harms of screening all young children whose parents and doctors had no concerns (an “I” statement). It did not recommend against screening, and an update is in progress [6][7]. The AAP continues to recommend universal screening because autism is common, can be diagnosed as young as 18 months, and has effective early supports [3]. In the UK, NICE says screening tools can help gather information but are not essential and must not be used to make or rule out a diagnosis [8].

How M-CHAT autism screening results work

Each answer that suggests a higher likelihood of autism scores 1 point. The official scoring algorithm is [1]:

• 0 to 2: low likelihood. No follow-up is needed. If your child is under 24 months, they should be screened again after their second birthday.
• 3 to 7: moderate likelihood. The clinician completes the Follow-Up questions. If the score stays at 2 or more, the screen is positive. If it falls to 0 or 1, it is negative.
• 8 to 20: high likelihood. The screen is positive, and the child can be referred straight away without the Follow-Up.

For a positive screen, the authors advise referring the child for both a diagnostic evaluation and an early intervention eligibility evaluation at the same time [1]. You do not have to wait for one before starting the other.

How accurate is M-CHAT autism screening?

In the main validation study of more than 16,000 toddlers screened at 18- and 24-month visits, children who screened positive after the Follow-Up had about a 48% chance of being diagnosed with autism, and about a 95% chance of having some developmental delay or concern [9]. So even when a positive screen is not autism, it usually points to something worth supporting.

A 2023 meta-analysis of 50 studies estimated that the M-CHAT (original and revised) correctly flags about 83% of autistic children and correctly clears about 94% of children who are not autistic, with wide variation between studies. It worked better when the Follow-Up interview was used [10].

Real-world results can be lower. In a large US pediatric network that screened nearly every child, the M-CHAT with Follow-Up picked up only about 39% of children later diagnosed with autism. Accuracy was lower for girls, children of color, and children from lower-income families, and sensitivity improved in older toddlers and with repeated screening [11]. This is why ongoing monitoring and your own observations matter, even after a “pass.”

Why screen at both 18 and 24 months?

Some autistic children do not show clear signs at 18 months, and some signs become more obvious as social expectations grow. In the large real-world study above, sensitivity was higher in older toddlers and when children were screened more than once [11]. That is why M-CHAT autism screening is repeated at 24 months, even if the first result was low.

What you can do at home

You can make M-CHAT autism screening more useful with a little preparation.

• Answer honestly. Describe what your child usually does, not what they did once or might do. There are no “good” or “bad” answers.
• Think of real examples before the visit. The Follow-Up asks for specific situations.
• Ask for your results and what they mean, whatever the score.
• Use the CDC milestone checklists alongside screening to track your child’s development between visits [12].
• Do not use online versions that are not from the official source; they may be altered and their scores may not be valid.

For signs to watch for, see early signs of autism in toddlers.

When to talk to a professional

If your child’s M-CHAT autism screening is positive, ask your doctor for a referral for a full developmental and autism evaluation, and contact your state’s early intervention program if your child is under 3. Anyone, including parents, can refer a child to early intervention, and no diagnosis is needed [13]. If the screen is negative but you are still worried, tell your doctor. The AAP says screening tools do not identify all autistic children, and your concerns as a parent are important [2]. Our guide to what happens at an autism assessment explains the next step.

Frequently asked questions

Can I do the M-CHAT at home?

The official M-CHAT-R/F can be downloaded free from its authors’ website, and some parents complete it before a checkup. However, it is designed to be scored and followed up by a clinician, and the Follow-Up interview is an important part of getting an accurate result. If you complete it at home, take it to your child’s doctor to discuss rather than relying on the score alone.

My child failed the M-CHAT. Does that mean autism?

No. A positive screen means a higher likelihood of autism, not a diagnosis. In the main validation study, about half of children who screened positive after the Follow-Up were later diagnosed with autism, and almost all had some developmental difference that benefited from support. The next step is a full evaluation and an early intervention referral.

My child passed the M-CHAT but I am still worried. What should I do?

Tell your doctor. No screening test catches every autistic child, and one large real-world study found the M-CHAT missed many children later diagnosed. Ask for further developmental screening, a hearing test, or a referral to a specialist. You can also contact early intervention directly if your child is under 3. Your observations are valuable information.

What age is the M-CHAT for?

The M-CHAT-R/F is designed for toddlers aged 16 to 30 months, and the AAP recommends autism screening at the 18- and 24-month checkups. The authors note it has been studied in children up to 48 months. For older children, clinicians use different questionnaires and assessments if autism is suspected.

References

1. Robins DL, Fein D, Barton M. Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F): official website, scoring and permissions (terminology update March 2025). Link
2. Blitz R, Swoboda S. How Pediatricians Screen for Autism. HealthyChildren.org (American Academy of Pediatrics). Last updated March 7, 2025. Link
3. Hyman SL, Levy SE, Myers SM; Council on Children With Disabilities, Section on Developmental and Behavioral Pediatrics. Identification, Evaluation, and Management of Children With Autism Spectrum Disorder. Pediatrics. 2020;145(1):e20193447. Link
4. Lipkin PH, Macias MM; Council on Children With Disabilities, Section on Developmental and Behavioral Pediatrics. Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening. Pediatrics. 2020;145(1):e20193449. Link
5. Centers for Disease Control and Prevention. Clinical Screening for Autism Spectrum Disorder. Last reviewed October 2, 2026. Link
6. Siu AL; US Preventive Services Task Force. Screening for Autism Spectrum Disorder in Young Children: US Preventive Services Task Force Recommendation Statement. JAMA. 2016;315(7):691-696. Link
7. US Preventive Services Task Force. Autism Spectrum Disorder in Young Children: Screening (final recommendation February 16, 2016; update in progress). Link
8. National Institute for Health and Care Excellence. Autism spectrum disorder in under 19s: recognition, referral and diagnosis. Clinical guideline CG128. Published 28 September 2011; last updated 20 December 2017 (minor changes 2021-2025). Link
9. Robins DL, Casagrande K, Barton M, Chen CM, Dumont-Mathieu T, Fein D. Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F). Pediatrics. 2014;133(1):37-45. Link
10. Wieckowski AT, Williams LN, Rando J, Lyall K, Robins DL. Sensitivity and Specificity of the Modified Checklist for Autism in Toddlers (Original and Revised): A Systematic Review and Meta-analysis. JAMA Pediatr. 2023;177(4):373-383. Link
11. Guthrie W, Wallis K, Bennett A, Brooks E, Dudley J, Gerdes M, et al. Accuracy of Autism Screening in a Large Pediatric Network. Pediatrics. 2019;144(4):e20183963. Link
12. Centers for Disease Control and Prevention, Learn the Signs. Act Early. CDC’s Developmental Milestones. Last reviewed February 17, 2026. Link
13. American Academy of Pediatrics. What is Early Intervention? HealthyChildren.org. Last updated December 23, 2025. Link

This guide is general education, not medical advice. Always talk to your child’s doctor or care team. Last checked: October 2026.