Validity and feasibility of using the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F) in primary care clinics in Singapore
Authors: Zheng Ruth Mingli , Chan Siew Pang , Law Evelyn C , Chong Shang Chee , Aishworiya Ramkumar 
Published: October 2023

Screening for autism in childhood has been advocated as a part of standard care. Challenges exist with screening implementation and performance of screening tools in clinical practice. This study aimed to examine the validity and feasibility of using the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F) for screening of autism in Singapore. Caregivers completed the M-CHAT-R/F as a part of the routine 18-month well-child visit in seven primary care clinics. Screening and follow-up interviews were administered by trained nursing staff. Children screened positive and a subset of those screened negative underwent diagnostic assessments for autism, which included an Autism Diagnostic Observation Schedule, Second Edition. Participants were 5336 multiethnic children (mean age 18.6 ± 0.9 months, 51.3% male gender). In total, 113 (2.1%) were screened positive, of which 54 (1.0%) were classified to have autism after their diagnostic assessment. Sensitivity of the M-CHAT-R/F was 88.6%, specificity 71.4%, and positive predictive value 90.7% for an autism diagnosis. The majority of respondents rated the screening process as feasible within the clinic setting. The M-CHAT-R/F had acceptable psychometric properties and high feasibility when used in primary care settings in Singapore. Recommendations for implementation of systematic screening and future research are presented. Lay abstract Systematic screening for autism in early childhood has been suggested to improve eventual outcomes by facilitating earlier diagnosis and access to intervention. However, clinical implementation of screening has to take into account effectiveness and feasibility of use within a healthcare setting for accurate diagnosis of autism. In Singapore, autism screening using a structured screening tool is not currently employed as a part of routine well-child visits for children in primary care clinics. In this study, 5336 children (aged 17–20 months) were screened for autism using the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F) during their 18-month well-child visit in seven primary care clinics. Screening and follow-up interviews were administered by nursing staff at each clinic. Children screened positive and a portion of those screened negative then underwent diagnostic assessments to determine whether they met the diagnostic criteria for autism. In total, 113 (2.1%) were screened positive, of which 54 (1.0%) met the criteria for autism. Children who screened positive and received a diagnosis accessed autism-specific intervention at an average age of 22 months. Nurses and physicians rated the acceptability and practicality of the M-CHAT-R/F highly. Therefore, the M-CHAT-R/F questionnaire was an effective and feasible tool for autism screening among 18-month-old children in this study. Future studies will be designed to determine the optimal age of screening and role of repeated screening in Singapore, as well as to better understand any potential improved outcomes nationwide compared with pre-implementation of autism screening.