1. To identify which diagnostic tools, including updated versions, most accurately diagnose ASD in preschool children when compared with multi‐disciplinary team clinical judgement.
2. To identify how the best of the interview tools compare with CARS, then how CARS compares with ADOS.
a. Which ASD diagnostic tool ‐ among ADOS, ADI‐R, CARS, DISCO, GARS, and 3di ‐ has the best diagnostic test accuracy?
b. Is the diagnostic test accuracy of any one test sufficient for that test to be suitable as a sole assessment tool for preschool children?
c. Is there any combination of tests that, if offered in sequence, would provide suitable diagnostic test accuracy and enhance test efficiency?
d. If data are available, does the combination of an interview tool with a structured observation test have better diagnostic test accuracy (i.e. fewer false‐positives and fewer false‐negatives) than either test alone?
As only one interview tool was identified, we modified the first three aims to a single aim (Differences between protocol and review): This Review evaluated diagnostic tests in terms of sensitivity and specificity.
We observed substantial variation in sensitivity and specificity of all tests, which was likely attributable to methodological differences and variations in the clinical characteristics of populations recruited.
When we compared summary statistics for ADOS, CARS, and ADI‐R, we found that ADOS was most sensitive. All tools performed similarly for specificity. In lower prevalence populations, the risk of falsely identifying children who do not have ASD would be higher.