A large national study aims to change that- or at least develop a test that can pinpoint children at greater risk for the disorder.
Twenty medical sites across the country, including Rush University Medical Center, will be studying the accuracy of a blood test for autism.
"It's looking for a specific sort of genetic marker where you can say if you have this you are at risk for having autism," said Dr. Michael Morrier, Emory Autism Center.
Right now the average age for an autism diagnosis in children is 4 ½. A test or screen could point to a diagnosis years earlier.
"It would basically be able to get kids into treatment earlier and really help some of the symptoms from developing, I believe," said Dr. Morrier.
That has big implications for treatment- especially for parents like Stephanie Medlin. Because autism can affect children's speech and ability to interact, Medlin believed something was wrong when her 2-year-old twins weren't talking much.
"They had about three or four words that they could use correctly and they should have had like 10 to 20 words," said Medlin.
It took months of behavioral tests, uncertainty and delays to find out it was autism.
"It's really hard to be a parent in that limbo because you absolutely want to do the best that you can for your children," said Medlin.
Medlin says the possibility of researchers coming up with a blood test that can immediately determine autism would be helpful for parents like herself.
"Had it been something that I could have just had a doctor say, 'Yes there you go.' It would have been fantastic," said Medlin.
However, even if the test works, doctors say it won't catch all autism cases. Still, they say narrowing down diagnoses for some patients could be a tremendous benefit.
Rush is looking for 50 children to participate in the study. They need to be between the ages of 18 months and 5-years-old.
For more information on the study:
Rush University Medical Center