The application of the Modified Checklist for Autism in Toddlers in Primary Health Care and its importance for early screening of autism spectrum disorder

Abstract

Introduction: Autism Spectrum Disorder (ASD) is a major public health issue, and its early detection facilitates timely interventions and better monitoring of child development. Primary Health Care (PHC) plays a strategic role in screening, and the adoption of standardized instruments, such as the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F), is supported by Brazilian child care policies within the Unified Health System (Sistema Único de Saúde – SUS). Objective: To analyze the available evidence on the use of the M-CHAT and its versions in PHC for early screening of ASD, identifying strengths and barriers related to its implementation. Methods: This is an integrative literature review, conducted based on a research question structured using the PICO strategy: “What is the evidence on the use of the M-CHAT in Primary Health Care for early screening of ASD?”. The search was conducted in PubMed, the Virtual Health Library (VHL/BVS), and Google Scholar. Primary studies published between 2015 and 2025, in Portuguese, English, and Spanish, that investigated the use of the M-CHAT in primary health care services or similar care settings, were included. After applying the eligibility criteria, 12 studies were selected for analysis. Results: The analyzed studies indicated that the M-CHAT and its versions are viable, low-cost instruments with adequate performance for early ASD screening in health services. The use of a follow-up interview proved important for reducing false-positive results, as well as conducting screenings at different stages of child development and training the professionals involved. However, barriers to its implementation were identified, such as service overload, limited knowledge among professionals regarding the instrument, and weaknesses in the integration between screening and referral processes for specialized diagnostic evaluation. Conclusions: The M-CHAT shows potential as a supportive tool for early ASD screening in Primary Health Care, facilitating the identification of at-risk children and timely referral for specialized evaluation. However, its implementation in the Unified Health System depends on educational strategies, the organization of work processes, and strengthening the pathways between screening, diagnosis, and intervention. The limited national scientific literature on its implementation and acceptability within the Brazilian PHC context highlights the need for further studies—especially longitudinal and intervention research—to contribute to the improvement of ASD screening strategies.