Screening recommendations vary worldwide. In the absence of evidence concerning the longer term outcomes of screened versus nonscreened children, more evidence is needed to determine the benefits of screening at the population level.[138]McPheeters ML, Weitlauf A, Vehorn A, et al.; US Preventive Services Task Force. Screening for autism spectrum disorder in young children: a systematic evidence review for the US Preventive Services Task Force: evidence synthesis no. 129. February 2016 [internet publication].
https://www.ncbi.nlm.nih.gov/books/NBK349703/pdf/Bookshelf_NBK349703.pdf
In the US, the American Academy of Pediatrics and the American Academy of Neurology recommend screening for ASD in primary care at regular checkups, starting during infancy.[29]Hyman SL, Levy SE, Myers SM, et al. Identification, evaluation, and management of children with autism spectrum disorder. Pediatrics. 2020 Jan;145(1):e20193447.
https://pediatrics.aappublications.org/content/145/1/e20193447.long
http://www.ncbi.nlm.nih.gov/pubmed/31843864?tool=bestpractice.com
Several screening tools have been developed for children >18 months and include the Checklist for Autism in Toddlers (CHAT) and the Modified Checklist for Autism in Toddlers (M-CHAT); screening tools for ASD for both children and adults typically have good sensitivity (e.g., 0.83 for M-CHAT) but poor specificity (e.g., 0.51 for M-CHAT).[139]Yuen T, Penner M, Carter MT, et al. Assessing the accuracy of the modified checklist for autism in toddlers: a systematic review and meta-analysis. Dev Med Child Neurol. 2018 Nov;60(11):1093-1100.
https://onlinelibrary.wiley.com/doi/full/10.1111/dmcn.13964
http://www.ncbi.nlm.nih.gov/pubmed/29992541?tool=bestpractice.com
For all ages, a positive screening result does not mean a definite diagnosis of ASD, and a negative result does not rule out ASD. Results may vary depending on the setting used and any comorbid mental health disorders.[140]Charman T, Gotham K. Measurement Issues: Screening and diagnostic instruments for autism spectrum disorders - lessons from research and practise. Child Adolesc Ment Health. 2013 Feb;18(1):52-63.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3607539
http://www.ncbi.nlm.nih.gov/pubmed/23539140?tool=bestpractice.com
Repeating the use of screening tools to monitor signs suggestive of ASD over time is generally recommended.[141]Zwaigenbaum L, Bauman ML, Choueiri R, et al. Early intervention for children with autism spectrum disorder under 3 years of age: recommendations for practice and research. Pediatrics. 2015 Oct;136 Suppl 1:S60-81.
http://www.ncbi.nlm.nih.gov/pubmed/26430170?tool=bestpractice.com
In other countries, such as the UK, widespread screening for ASD is not currently recommended. Instead, healthcare professionals are encouraged to remain vigilant for any signs that may indicate ASD, and to take regular opportunities to discuss the child's development with the parents as part of existing health surveillance programs.
The American Academy of Neurology and Child Neurology Society have produced red flags for ASD.[142]Filipek P, Accardo PG, Ashwal S, et al. Practice parameter: screening and diagnosis of autism: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society. Neurology. 2000 Aug 22;55(4):468-79.
http://www.neurology.org/content/55/4/468.full
http://www.ncbi.nlm.nih.gov/pubmed/10953176?tool=bestpractice.com
If any of these are present, they recommend further evaluation:
No babbling or pointing or other gesture by 12 months
No single words by 16 months
No two-word spontaneous (not echolalic) phrases by 24 months
Loss of language or social skills at any age.