Although ASD can be reliably diagnosed in children at about 2 years of age, on average, children in the U.S. are not diagnosed until they are 4 to 5 years old. Early diagnosis allows for early intervention, which improves outcomes, including quality of life. Previous studies have found associations between delayed diagnosis and factors, such as: low socioeconomic status, racial or ethnic minority status, low levels of caregiver awareness, inadequate community of symptoms, presumably due to later intervention. To increase early diagnosis and early intervention, several Federal and national agencies have promoted effective community approaches to early detection (screening to identify order to compare different approaches with respect to populations studied, intervention components, and outcomes.They reviewed 40 screening studies, which they sorted into the following categories: (1) strategies to raise awareness about early detection; (2) routine screening in medical and nonmedical settings; and (3) practices aimed at improvingscreening, such as provider training.

Of the four studies that described approaches focused on raising awareness about screening in parents, clinicians, andchild care professionals, one reported positive results from a 3-year social media campaign. The other three studiesassessed the effectiveness of training providers (online or in-person) to recognize ASD or developmental delays(DD). Two of these studies showed positive results, but the most scientifically rigorous study showed no difference inprovider knowledge after training. Regarding routine screening, which includes screening using standardized surveysor other types of evaluations, 25 studies described 21 approaches to screening for DD, ASD, or both. Fifteen screeningprograms were conducted in health care settings; the others were in community settings. Researchers found thatthe literature reflected a wide variety of screening tools used and a wide variety of outcome measures, including screening rates and the percentage of children who screen positive who are referred for further evaluation. Most, but not all, screenings that took place in primary care settings happened during the recommended well-child care visits. Some children were screened when they were sick, for example. Only a few studies looked at the change in how many children screened positive and were referred in response to a routine screening intervention. Of those studies, all reported an increase in rates of children screening positive or in rates of referral to intervention, indicating that medical or community-based opportunities for routine screening increase the likelihood that children who need services will be identified. However, more research is needed to connect these increased rates of referral with earlier diagnosis and access to services. The remaining 11 studies focused on 10 ways to enhance screening. A wide range of screening and referral rates was observed in these studies. Screening rates may be improved with a multifaceted approach that includes training clinicians in DD and ASD, ensuring they have validated screening tools, informing them about reimbursement practices, and providing resources for referrals, including partnerships with specialty providers. Going forward, improving the rigor of approaches to early detection and ensuring underserved populations benefit from evidence-based approaches should be high priorities. Establishing state-level benchmarks for early detection may also encourage better tracking.

The Modified Checklist for Autism in Toddlers (M-CHAT) is one of the worldfs most widely used, validated screening tools, and it consists of a questionnaire administered to parents about their childfs behaviors. Optimally, a screening tool should be reliable and accurately identify children with signs of autism and also minimize the likelihood that some screened children will be incorrectly referred for unnecessary follow-up. In this study, researchers tested the M-CHAT, Revised with Follow-Up (M-CHAT-R/F) to determine if the modifications to the survey improved the ability to detect ASD in 18- and 24-month toddlers. Five revisions were made: (1) three M-CHAT/F questions that did not strongly help identify ASD were dropped; (2) the remaining 20 questions were reorganized to elicit more accurate answers from parents; (3) the top seven items that best differentiated ASD from other disorders were placed among the first 10 questions asked; (4) language was simplified (e.g., gDoes your child ever use his/her index finger to pointch was changed to “Does your child point with one finger…” ); and (5) examples of behaviors were given to provide additional context. The revised tool (M-CHAT-R/F) remains a two-stage screener. First, providers ask parents to answer 20 yes/no questions, which takes less than 5 minutes. If their child screens positive, parents spend an additional 5 to 10 minutes answering follow-up questions. Providers in metropolitan Atlanta and Connecticut screened 15,612 toddlers (average age 2 years, 2 months). A checkbox on the screener allowed the provider to indicate an independent concern about ASD. Based on parent response, researchers classified the children as low-, medium-, or high-risk for ASD. Parents of children at low risk were not asked to complete the follow-up questionnaire unless the provider had indicated a concern. Parents of children in the medium-risk group were contacted by telephone by the research staff to complete the follow-up. Those whose children were in the high-risk range were not contacted for follow-up, but were directly referred for evaluation. Children that were considered high-risk were those whose total scores were >3 in the first stage of the survey and then had a total score of >2 after follow-up. Of those children in the high-risk group, 47.5% were at risk of being diagnosed with ASD and 94.6% were at risk of any developmental delay. More than half of the medium-risk children no longer showed risk after the second stage of screening. Children continuing to screen positive and those flagged by providers were offered evaluation. Compared with the original tool, M-CHAT-R/F performed well in detecting toddlers with ASD while reducing unnecessary follow-up among children without ASD. The M-CHAT-R/F may be valued by busy medical offices and parents, as results show there is little to be gained by advancing low-risk or high-risk children to Stage 2 screening. Low-risk children can be screened again at a later date, as recommended. High-risk children, whose Stage 1 scores indicate they will continue to score high on a Stage 2 screening, can advance directly to evaluation. This study demonstrates that the M-CHAT-R/F can detect ASD in children 2 years old—2 years earlier than most cases are currently diagnosed—which optimizes the opportunity for early intervention.