Large-scale use of the modified checklist for autism in low-risk toddlers

Abstract

Objective: The purpose of the study was to examine use of the Modified Checklist for Autism in Toddlers (M-CHAT) as an autism-specific screening instrument in a large, geographically diverse pediatrics-based sample.

Methods: The M-CHAT and the M-CHAT Follow-Up (M-CHAT/F) were used to screen 18,989 toddlers at pediatric well-child visits in 2 US geographic regions. Pediatricians directly referred children to ascertain potential missed screening cases. Screen-positive children received the M-CHAT/F; children who continued to screen positive after the M-CHAT/F received a diagnostic evaluation.

Results: Results indicated that 54% of children who screened positive on the M-CHAT and M-CHAT/F presented with an autism spectrum disorder (ASD), and 98% presented with clinically significant developmental concerns warranting intervention. An M-CHAT total score cutoff of ≥3 identifies nearly all screen-positive cases, and for ease of scoring the use of only the M-CHAT total score cutoff is recommended. An M-CHAT total score of 7 serves as an appropriate clinical cutoff, and providers can bypass the M-CHAT/F and refer immediately to evaluation and intervention if a child obtains a score of ≥7.

Conclusions: This study provides empirical support for the utility of population screening for ASD with the use of the M-CHAT in a primary care setting. Results suggest that the M-CHAT continues to be an effective screening instrument for ASD when the 2-step screening process is used. The M-CHAT is widely used at pediatric offices, and this study provides updated results to facilitate use and scoring of the M-CHAT by clinical providers.

FIGURE 1

Study participation flowchart. The bold lines indicate the standard path of participation in the study; the dashed lines indicate ways in which children received evaluations as potential missed screening cases. ^aOf the 422 M-CHAT/F noncompleters, 271 were unable to be contacted for follow-up, 38 declined additional participation, 5 were excluded due to a language barrier, 6 received an evaluation without completing the M-CHAT/F due to failing a high number of items on the M-CHAT (indicating a high risk of ASD), and 122 cases had missing data. ^b“High Fails” refers to children who screened positive on ≥8 items on the M-CHAT screening questionnaire (indicating a high risk of ASD) and who were referred directly to evaluation, bypassing the M-CHAT/F. ^cOf the 107 children who did not complete an evaluation, 65 declined an evaluation or failed to show up for multiple appointments; 22 could not be contacted to schedule the evaluation; 7 were excluded due to a previous medical diagnosis or the presence of a severe neurologic, physical, visual, or hearing deficit that precluded the child’s ability to complete the standardized evaluation measures; and 13 cases had missing data. STAT, Screening Tool for Autism in Two-Year-Olds.