The American Academy of Pediatrics (AAP) recommends that all children receive autism screening at 18 and 24 months of age, and the M-CHAT is one of the AAP’s recommended tools.
The M-CHAT’s primary goal is to detect as many cases of ASD as possible. Therefore, there is a high false positive rate, meaning that many children who score at risk for ASD will not be diagnosed with ASD. To address this, the authors developed a structured M-CHAT Follow-up InterviewTM (downloadable here).
Even with the follow-up questions, a significant number of children whose results show risk for ASD will not meet the diagnostic criteria on a more comprehensive evaluation by a specialist. Nonetheless, these children are at risk for a range of developmental disorders and delays and, therefore, should receive further evaluation. Conversely, a child should be referred for further evaluation any time a parent or professional has persistent concerns about autism, even if the child does not show ASD risk on the M-CHAT.