M-CHAT-R/F Score Interpretation

Why use it

The AAP recommends autism-specific screening at the 18- and 24-month visits (Hyman et al., Pediatrics 2020; Lipkin & Macias, Pediatrics 2020). Applying the published three-level algorithm consistently, including the Follow-Up step for moderate scores, is what gives the M-CHAT-R/F its validated performance (Robins et al., Pediatrics 2014).

About

The Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F) is a two-stage parent-report screening tool for autism. The M-CHAT-R has 20 items, and the total is the number of responses that indicate elevated likelihood. Total 0–2 is low likelihood; 3–7 is moderate likelihood, for which the structured Follow-Up interview is administered; 8–20 is high likelihood, for which the Follow-Up may be bypassed and the child referred immediately. After the Follow-Up, the screen is positive when the child still scores at high likelihood on two or more items. This calculator takes the totals obtained on the official form and returns the corresponding step of the official algorithm; it does not contain or reproduce the items. The form and its instructions are available free of charge from mchatscreen.com for clinical, research and educational use.

When to use

• Autism screening at the 18- and 24-month health supervision visits
• When a parent or clinician raises a concern about social communication in a child aged 16–30 months
• Children 16 to 48 months old, the range the authors state studies have used

Formula

Pearls & pitfalls

• The Follow-Up interview is the second stage of the validated instrument: for totals of 3–7 the screen result is defined only after it.
• Concern about autism from the clinician or parent warrants referral regardless of the M-CHAT-R or M-CHAT-R/F score (official instructions).
• A negative screen does not exclude autism; continue surveillance at every visit.
• The tool is copyrighted and free for clinical, research and educational use; electronic or commercial use requires permission from the authors. This calculator records the totals only.
• Use the current form (terminology update March 2025) from mchatscreen.com.

Next steps

Low likelihood (0–2): if the child is younger than 24 months, screen again after the second birthday. Moderate likelihood (3–7): administer the Follow-Up; a Follow-Up score of 2 or more is a positive screen. High likelihood (8–20) or positive Follow-Up: refer for diagnostic evaluation and eligibility evaluation for early intervention. If the clinician or parent has concerns about autism, refer regardless of the score.

Evidence

Validation: Robins et al., Pediatrics 2014;133:37-45. Children whose total score was ≥ 3 initially and ≥ 2 after Follow-Up had a 47.5% risk of being diagnosed with autism spectrum disorder and a 94.6% risk of any developmental delay or concern; the authors recommended an algorithm based on 3 risk levels. Algorithm text: official M-CHAT-R/F form, March 2025, p. 2 (Scoring Algorithm) and p. 4 (Follow-Up instructions).

References

1. Robins DL, Fein D, Barton M. Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F). © 2009; terminology update March 4, 2025. — link
2. 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
3. Hyman SL, Levy SE, Myers SM; AAP Council on Children with Disabilities. Identification, Evaluation, and Management of Children With Autism Spectrum Disorder. Pediatrics. 2020;145(1):e20193447. — link
4. Lipkin PH, Macias MM; AAP. Promoting Optimal Development: Identifying Infants and Young Children With Developmental Disorders Through Developmental Surveillance and Screening. Pediatrics. 2020;145(1):e20193449. — link