I came across this new update about autism recently. Screening tests for autism spectrum disorder (ASD) should be interpreted on a case by case basis and in the context of overall development of the child.
There was a recent prospective cohort, 228 of >68,000 children who screened negative for ASD at age 18 months were subsequently diagnosed with ASD. Although they passed the ASD screen, they had abnormalities or delays in social, communication, or motor skills on other developmental/behavior screens.
If there is still concern for the child who screen negative for ASD at 18 or 24 months the child should continue to undergo routine developmental/behavioral screening. Those who have abnormal or delayed social or communication skills should be referred for a comprehensive developmental/behavioral evaluation regardless of the results of the ASD screen.
Basically, children change and grow rapidly at times. They are dynamic and not static. I think the moral of this update is that if a parent gets news that their child does not have ASD, but the parent still has concerns, then the issue should be revisited.