According to an article in Pediatrics journal/magazine (Guthrie W. et al.), the standard test being used to detect autism is not doing its job. Many children are misdiagnosed as being on the spectrum while those who actually are on the spectrum are not recognized.
The test, called the Modified Checklist for Autism in Toddlers (M-CHAT), is correctly identifying less than 40% of children with autism. At the same time, 85% of the children the test identifies as being autistic are false positives, meaning they are not on the spectrum at all! This new study mirrors previous results found in Malaysian and Norwegian surveys. So this means that children who require services will not receive them while neurotypical children will receive services they do not need while worrying the parents unnecessarily.
It is worth mentioning that repeat-testing resulted in more accurate results, while many of the children who scored false-negative results did end up needing services for other conditions, so the test was not a total waste of time and resources. Clearly, this illustrates the need for a different, more accurate test for autism.